BMAKE(1)                FreeBSD General Commands Manual               BMAKE(1)

NNAAMMEE
     bbmmaakkee - maintain program dependencies

SSYYNNOOPPSSIISS
     bbmmaakkee [--BBeeiikkNNnnqqrrSSssttWWwwXX] [--CC _d_i_r_e_c_t_o_r_y] [--DD _v_a_r_i_a_b_l_e] [--dd _f_l_a_g_s]
           [--ff _m_a_k_e_f_i_l_e] [--II _d_i_r_e_c_t_o_r_y] [--JJ _p_r_i_v_a_t_e] [--jj _m_a_x___j_o_b_s]
           [--mm _d_i_r_e_c_t_o_r_y] [--TT _f_i_l_e] [--VV _v_a_r_i_a_b_l_e] [--vv _v_a_r_i_a_b_l_e]
           [_v_a_r_i_a_b_l_e==_v_a_l_u_e] [_t_a_r_g_e_t ...]

DDEESSCCRRIIPPTTIIOONN
     bbmmaakkee is a program designed to simplify the maintenance of other
     programs.  Its input is a list of specifications as to the files upon
     which programs and other files depend.  If no --ff _m_a_k_e_f_i_l_e option is
     given, bbmmaakkee looks for the makefiles listed in _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E
     (default `_m_a_k_e_f_i_l_e', `_M_a_k_e_f_i_l_e') in order to find the specifications.  If
     the file `_._d_e_p_e_n_d' exists, it is read, see mkdep(1).

     This manual page is intended as a reference document only.  For a more
     thorough description of bbmmaakkee and makefiles, please refer to _P_M_a_k_e _- _A
     _T_u_t_o_r_i_a_l (from 1993).

     bbmmaakkee prepends the contents of the MAKEFLAGS environment variable to the
     command line arguments before parsing them.

     The options are as follows:

     --BB      Try to be backwards compatible by executing a single shell per
             command and by making the sources of a dependency line in
             sequence.

     --CC _d_i_r_e_c_t_o_r_y
             Change to _d_i_r_e_c_t_o_r_y before reading the makefiles or doing
             anything else.  If multiple --CC options are specified, each is
             interpreted relative to the previous one: --CC _/ --CC _e_t_c is
             equivalent to --CC _/_e_t_c.

     --DD _v_a_r_i_a_b_l_e
             Define _v_a_r_i_a_b_l_e to be 1, in the global scope.

     --dd [--]_f_l_a_g_s
             Turn on debugging, and specify which portions of bbmmaakkee are to
             print debugging information.  Unless the flags are preceded by
             `-', they are added to the MAKEFLAGS environment variable and are
             passed on to any child make processes.  By default, debugging
             information is printed to standard error, but this can be changed
             using the FF debugging flag.  The debugging output is always
             unbuffered; in addition, if debugging is enabled but debugging
             output is not directed to standard output, the standard output is
             line buffered.  The available _f_l_a_g_s are:

             AA       Print all possible debugging information; equivalent to
                     specifying all of the debugging flags.

             aa       Print debugging information about archive searching and
                     caching.

             CC       Print debugging information about the current working
                     directory.

             cc       Print debugging information about conditional evaluation.

             dd       Print debugging information about directory searching and
                     caching.

             ee       Print debugging information about failed commands and
                     targets.

             FF[++]_f_i_l_e_n_a_m_e
                     Specify where debugging output is written.  This must be
                     the last flag, because it consumes the remainder of the
                     argument.  If the character immediately after the FF flag
                     is `+', the file is opened in append mode; otherwise the
                     file is overwritten.  If the file name is `stdout' or
                     `stderr', debugging output is written to the standard
                     output or standard error output respectively (and the `+'
                     option has no effect).  Otherwise, the output is written
                     to the named file.  If the file name ends with `.%d', the
                     `%d' is replaced by the pid.

             ff       Print debugging information about loop evaluation.

             gg11      Print the input graph before making anything.

             gg22      Print the input graph after making everything, or before
                     exiting on error.

             gg33      Print the input graph before exiting on error.

             hh       Print debugging information about hash table operations.

             jj       Print debugging information about running multiple
                     shells.

             LL       Turn on lint checks.  This throws errors for variable
                     assignments that do not parse correctly, at the time of
                     assignment, so the file and line number are available.

             ll       Print commands in Makefiles regardless of whether or not
                     they are prefixed by `@' or other "quiet" flags.  Also
                     known as "loud" behavior.

             MM       Print debugging information about "meta" mode decisions
                     about targets.

             mm       Print debugging information about making targets,
                     including modification dates.

             nn       Don't delete the temporary command scripts created when
                     running commands.  These temporary scripts are created in
                     the directory referred to by the TMPDIR environment
                     variable, or in _/_t_m_p if TMPDIR is unset or set to the
                     empty string.  The temporary scripts are created by
                     mkstemp(3), and have names of the form _m_a_k_e_X_X_X_X_X_X.  _N_O_T_E:
                     This can create many files in TMPDIR or _/_t_m_p, so use with
                     care.

             pp       Print debugging information about makefile parsing.

             ss       Print debugging information about suffix-transformation
                     rules.

             tt       Print debugging information about target list
                     maintenance.

             VV       Force the --VV option to print raw values of variables,
                     overriding the default behavior set via
                     _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S.

             vv       Print debugging information about variable assignment and
                     expansion.

             xx       Run shell commands with --xx so the actual commands are
                     printed as they are executed.

     --ee      Let environment variables override global variables within
             makefiles.

     --ff _m_a_k_e_f_i_l_e
             Specify a makefile to read instead of one of the defaults listed
             in _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E.  If _m_a_k_e_f_i_l_e is `-', standard input
             is read.  If _m_a_k_e_f_i_l_e starts with the string `.../', bbmmaakkee
             searches for the specified path in the rest of the argument in
             the current directory and its parents.  Multiple makefiles may be
             specified, and are read in the order specified.

     --II _d_i_r_e_c_t_o_r_y
             Specify a directory in which to search for makefiles and included
             makefiles.  The system makefile directory (or directories, see
             the --mm option) is automatically included as part of this list.

     --ii      Ignore non-zero exit of shell commands in the makefile.
             Equivalent to specifying `-' before each command line in the
             makefile.

     --JJ _p_r_i_v_a_t_e
             This option should _n_o_t be specified by the user.

             When the --jj option is in use in a recursive build, this option is
             passed by a make to child makes to allow all the make processes
             in the build to cooperate to avoid overloading the system.

     --jj _m_a_x___j_o_b_s
             Specify the maximum number of jobs that bbmmaakkee may have running at
             any one time.  If _m_a_x___j_o_b_s is a floating point number, or ends
             with `C', then the value is multiplied by the number of CPUs
             reported online by sysconf(3).  The value of _m_a_x___j_o_b_s is saved in
             _._M_A_K_E_._J_O_B_S.  Turns compatibility mode off, unless the --BB option
             is also specified.  When compatibility mode is off, all commands
             associated with a target are executed in a single shell
             invocation as opposed to the traditional one shell invocation per
             line.  This can break traditional scripts which change
             directories on each command invocation and then expect to start
             with a fresh environment on the next line.  It is more efficient
             to correct the scripts rather than turn backwards compatibility
             on.

             A job token pool with _m_a_x___j_o_b_s tokens is used to control the
             total number of jobs running.  Each instance of bbmmaakkee will wait
             for a token from the pool before running a new job.

     --kk      Continue processing after errors are encountered, but only on
             those targets that do not depend on the target whose creation
             caused the error.

     --mm _d_i_r_e_c_t_o_r_y
             Specify a directory in which to search for _s_y_s_._m_k and makefiles
             included via the <_f_i_l_e>-style include statement.  The --mm option
             can be used multiple times to form a search path.  This path
             overrides the default system include path _/_u_s_r_/_s_h_a_r_e_/_m_k.
             Furthermore, the system include path is appended to the search
             path used for "_f_i_l_e"-style include statements (see the --II
             option).  The system include path can be referenced via the read-
             only variable _._S_Y_S_P_A_T_H.

             If a directory name in the --mm argument (or the MAKESYSPATH
             environment variable) starts with the string `.../', bbmmaakkee
             searches for the specified file or directory named in the
             remaining part of the argument string.  The search starts with
             the current directory and then works upward towards the root of
             the file system.  If the search is successful, the resulting
             directory replaces the `.../' specification in the --mm argument.
             This feature allows bbmmaakkee to easily search in the current source
             tree for customized _s_y_s_._m_k files (e.g., by using `.../mk/sys.mk'
             as an argument).

     --nn      Display the commands that would have been executed, but do not
             actually execute them unless the target depends on the _._M_A_K_E
             special source (see below) or the command is prefixed with `++'.

     --NN      Display the commands that would have been executed, but do not
             actually execute any of them; useful for debugging top-level
             makefiles without descending into subdirectories.

     --qq      Do not execute any commands, instead exit 0 if the specified
             targets are up to date, and 1 otherwise.

     --rr      Do not use the built-in rules specified in the system makefile.

     --SS      Stop processing if an error is encountered.  This is the default
             behavior and the opposite of --kk.

     --ss      Do not echo any commands as they are executed.  Equivalent to
             specifying `@@' before each command line in the makefile.

     --TT _t_r_a_c_e_f_i_l_e
             When used with the --jj flag, append a trace record to _t_r_a_c_e_f_i_l_e
             for each job started and completed.

     --tt      Rather than re-building a target as specified in the makefile,
             create it or update its modification time to make it appear up-
             to-date.

     --VV _v_a_r_i_a_b_l_e
             Print the value of _v_a_r_i_a_b_l_e.  Do not build any targets.  Multiple
             instances of this option may be specified; the variables are
             printed one per line, with a blank line for each null or
             undefined variable.  The value printed is extracted from the
             global scope after all makefiles have been read.

             By default, the raw variable contents (which may include
             additional unexpanded variable references) are shown.  If
             _v_a_r_i_a_b_l_e contains a `$', it is not interpreted as a variable name
             but rather as an expression.  Its value is expanded before
             printing.  The value is also expanded before printing if
             _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S is set to true and the --ddVV option has not
             been used to override it.

             Note that loop-local and target-local variables, as well as
             values taken temporarily by global variables during makefile
             processing, are not accessible via this option.  The --ddvv debug
             mode can be used to see these at the cost of generating
             substantial extraneous output.

     --vv _v_a_r_i_a_b_l_e
             Like --VV, but all printed variables are always expanded to their
             complete value.  The last occurrence of --VV or --vv decides whether
             all variables are expanded or not.

     --WW      Treat any warnings during makefile parsing as errors.

     --ww      Print entering and leaving directory messages, pre and post
             processing.

     --XX      Don't export variables passed on the command line to the
             environment individually.  Variables passed on the command line
             are still exported via the MAKEFLAGS environment variable.  This
             option may be useful on systems which have a small limit on the
             size of command arguments.

     _v_a_r_i_a_b_l_e==_v_a_l_u_e
             Set the value of the variable _v_a_r_i_a_b_l_e to _v_a_l_u_e.  Normally, all
             values passed on the command line are also exported to sub-makes
             in the environment.  The --XX flag disables this behavior.
             Variable assignments should follow options for POSIX
             compatibility but no ordering is enforced.

     There are several different types of lines in a makefile: dependency
     specifications, shell commands, variable assignments, include statements,
     conditional directives, for loops, other directives, and comments.

     Lines may be continued from one line to the next by ending them with a
     backslash (`\').  The trailing newline character and initial whitespace
     on the following line are compressed into a single space.

FFIILLEE DDEEPPEENNDDEENNCCYY SSPPEECCIIFFIICCAATTIIOONNSS
     Dependency lines consist of one or more targets, an operator, and zero or
     more sources.  This creates a relationship where the targets "depend" on
     the sources and are customarily created from them.  A target is
     considered out of date if it does not exist, or if its modification time
     is less than that of any of its sources.  An out-of-date target is re-
     created, but not until all sources have been examined and themselves re-
     created as needed.  Three operators may be used:

     ::     Many dependency lines may name this target but only one may have
           attached shell commands.  All sources named in all dependency lines
           are considered together, and if needed the attached shell commands
           are run to create or re-create the target.  If bbmmaakkee is
           interrupted, the target is removed.

     !!     The same, but the target is always re-created whether or not it is
           out of date.

     ::::    Any dependency line may have attached shell commands, but each one
           is handled independently: its sources are considered and the
           attached shell commands are run if the target is out of date with
           respect to (only) those sources.  Thus, different groups of the
           attached shell commands may be run depending on the circumstances.
           Furthermore, unlike ::, for dependency lines with no sources, the
           attached shell commands are always run.  Also unlike ::, the target
           is not removed if bbmmaakkee is interrupted.

     All dependency lines mentioning a particular target must use the same
     operator.

     Targets and sources may contain the shell wildcard values `?', `*', `[]',
     and `{}'.  The values `?', `*', and `[]' may only be used as part of the
     final component of the target or source, and only match existing files.
     The value `{}' need not necessarily be used to describe existing files.
     Expansion is in directory order, not alphabetically as done in the shell.

SSHHEELLLL CCOOMMMMAANNDDSS
     Each target may have associated with it one or more lines of shell
     commands, normally used to create the target.  Each of the lines in this
     script _m_u_s_t be preceded by a tab.  (For historical reasons, spaces are
     not accepted.)  While targets can occur in many dependency lines if
     desired, by default only one of these rules may be followed by a creation
     script.  If the `::::' operator is used, however, all rules may include
     scripts, and the respective scripts are executed in the order found.

     Each line is treated as a separate shell command, unless the end of line
     is escaped with a backslash `\', in which case that line and the next are
     combined.  If the first characters of the command are any combination of
     `@@', `++', or `--', the command is treated specially.

           @@       causes the command not to be echoed before it is executed.

           ++       causes the command to be executed even when --nn is given.
                   This is similar to the effect of the _._M_A_K_E special source,
                   except that the effect can be limited to a single line of a
                   script.

           --       in compatibility mode causes any non-zero exit status of
                   the command line to be ignored.

     When bbmmaakkee is run in jobs mode with --jj _m_a_x___j_o_b_s, the entire script for
     the target is fed to a single instance of the shell.  In compatibility
     (non-jobs) mode, each command is run in a separate process.  If the
     command contains any shell meta characters (`#=|^(){};&<>*?[]:$`\\n'), it
     is passed to the shell; otherwise bbmmaakkee attempts direct execution.  If a
     line starts with `--' and the shell has ErrCtl enabled, failure of the
     command line is ignored as in compatibility mode.  Otherwise `--' affects
     the entire job; the script stops at the first command line that fails,
     but the target is not deemed to have failed.

     Makefiles should be written so that the mode of bbmmaakkee operation does not
     change their behavior.  For example, any command which uses "cd" or
     "chdir" without the intention of changing the directory for subsequent
     commands should be put in parentheses so it executes in a subshell.  To
     force the use of a single shell, escape the line breaks so as to make the
     whole script one command.  For example:

           avoid-chdir-side-effects:
                   @echo "Building $@ in $$(pwd)"
                   @(cd ${.CURDIR} && ${MAKE} $@)
                   @echo "Back in $$(pwd)"

           ensure-one-shell-regardless-of-mode:
                   @echo "Building $@ in $$(pwd)"; \
                   (cd ${.CURDIR} && ${MAKE} $@); \
                   echo "Back in $$(pwd)"

     Since bbmmaakkee changes the current working directory to `_._O_B_J_D_I_R' before
     executing any targets, each child process starts with that as its current
     working directory.

VVAARRIIAABBLLEE AASSSSIIGGNNMMEENNTTSS
     Variables in make behave much like macros in the C preprocessor.

     Variable assignments have the form `_N_A_M_E _o_p _v_a_l_u_e', where:

           _N_A_M_E    is a single-word variable name, consisting, by tradition,
                   of all upper-case letters,

           _o_p      is one of the variable assignment operators described
                   below, and

           _v_a_l_u_e   is interpreted according to the variable assignment
                   operator.

     Whitespace around _N_A_M_E, _o_p and _v_a_l_u_e is discarded.

   VVaarriiaabbllee aassssiiggnnmmeenntt ooppeerraattoorrss
     The five operators that assign values to variables are:

     ==       Assign the value to the variable.  Any previous value is
             overwritten.

     ++==      Append the value to the current value of the variable, separating
             them by a single space.

     ??==      Assign the value to the variable if it is not already defined.

     ::==      Expand the value, then assign it to the variable.

             _N_O_T_E: References to undefined variables are _n_o_t expanded.  This
             can cause problems when variable modifiers are used.

     !!==      Expand the value and pass it to the shell for execution, then
             assign the output from the child's standard output to the
             variable.  Any newlines in the result are replaced with spaces.

   EExxppaannssiioonn ooff vvaarriiaabblleess
     In most contexts where variables are expanded, `$$' expands to a single
     dollar sign.  In other contexts (most variable modifiers, string literals
     in conditions), `\$' expands to a single dollar sign.

     References to variables have the form $${{_n_a_m_e[::_m_o_d_i_f_i_e_r_s]}} or
     $$((_n_a_m_e[::_m_o_d_i_f_i_e_r_s])).  If the variable name consists of only a single
     character and the expression contains no modifiers, the surrounding curly
     braces or parentheses are not required.  This shorter form is not
     recommended.

     If the variable name contains a dollar, the name itself is expanded
     first.  This allows almost arbitrary variable names, however names
     containing dollar, braces, parentheses or whitespace are really best
     avoided.

     If the result of expanding a nested variable expression contains a dollar
     sign (`$'), the result is subject to further expansion.

     Variable substitution occurs at four distinct times, depending on where
     the variable is being used.

     1.   Variables in dependency lines are expanded as the line is read.

     2.   Variables in conditionals are expanded individually, but only as far
          as necessary to determine the result of the conditional.

     3.   Variables in shell commands are expanded when the shell command is
          executed.

     4.   ..ffoorr loop index variables are expanded on each loop iteration.  Note
          that other variables are not expanded when composing the body of a
          loop, so the following example code:

                .for i in 1 2 3
                a+=     ${i}
                j=      ${i}
                b+=     ${j}
                .endfor

                all:
                        @echo ${a}
                        @echo ${b}

          prints:

                1 2 3
                3 3 3

          After the loop is executed:

                _a       contains `${:U1} ${:U2} ${:U3}', which expands to `1 2
                        3'.

                _j       contains `${:U3}', which expands to `3'.

                _b       contains `${j} ${j} ${j}', which expands to `${:U3}
                        ${:U3} ${:U3}' and further to `3 3 3'.

   VVaarriiaabbllee ccllaasssseess
     The four different classes of variables (in order of increasing
     precedence) are:

     Environment variables
             Variables defined as part of bbmmaakkee's environment.

     Global variables
             Variables defined in the makefile or in included makefiles.

     Command line variables
             Variables defined as part of the command line.

     Local variables
             Variables that are defined specific to a certain target.

     Local variables can be set on a dependency line, unless
     _._M_A_K_E_._T_A_R_G_E_T___L_O_C_A_L___V_A_R_I_A_B_L_E_S is set to `false'.  The rest of the line
     (which already has had global variables expanded) is the variable value.
     For example:

           COMPILER_WRAPPERS= ccache distcc icecc

           ${OBJS}: .MAKE.META.CMP_FILTER=${COMPILER_WRAPPERS:S,^,N,}

     Only the targets `${OBJS}' are impacted by that filter (in "meta" mode)
     and simply enabling/disabling any of the compiler wrappers does not
     render all of those targets out-of-date.

     _N_O_T_E: target-local variable assignments behave differently in that;

           ++==      Only appends to a previous local assignment for the same
                   target and variable.

           ::==      Is redundant with respect to global variables, which have
                   already been expanded.

     The seven built-in local variables are:

           _._A_L_L_S_R_C   The list of all sources for this target; also known as
                     `_>'.

           _._A_R_C_H_I_V_E  The name of the archive file; also known as `_!'.

           _._I_M_P_S_R_C   In suffix-transformation rules, the name/path of the
                     source from which the target is to be transformed (the
                     "implied" source); also known as `_<'.  It is not defined
                     in explicit rules.

           _._M_E_M_B_E_R   The name of the archive member; also known as `_%'.

           _._O_O_D_A_T_E   The list of sources for this target that were deemed out-
                     of-date; also known as `_?'.

           _._P_R_E_F_I_X   The name of the target with suffix (if declared in
                     ..SSUUFFFFIIXXEESS) removed; also known as `_*'.

           _._T_A_R_G_E_T   The name of the target; also known as `_@'.  For
                     compatibility with other makes this is an alias for
                     _._A_R_C_H_I_V_E in archive member rules.

     The shorter forms (`_>', `_!', `_<', `_%', `_?', `_*', and `_@') are permitted
     for backward compatibility with historical makefiles and legacy POSIX
     make and are not recommended.

     Variants of these variables with the punctuation followed immediately by
     `D' or `F', e.g. `$(@D)', are legacy forms equivalent to using the `:H'
     and `:T' modifiers.  These forms are accepted for compatibility with AT&T
     System V UNIX makefiles and POSIX but are not recommended.

     Four of the local variables may be used in sources on dependency lines
     because they expand to the proper value for each target on the line.
     These variables are `_._T_A_R_G_E_T', `_._P_R_E_F_I_X', `_._A_R_C_H_I_V_E', and `_._M_E_M_B_E_R'.

   AAddddiittiioonnaall bbuuiilltt--iinn vvaarriiaabblleess
     In addition, bbmmaakkee sets or knows about the following variables:

     _._A_L_L_T_A_R_G_E_T_S
             The list of all targets encountered in the makefiles.  If
             evaluated during makefile parsing, lists only those targets
             encountered thus far.

     _._C_U_R_D_I_R
             A path to the directory where bbmmaakkee was executed.  Refer to the
             description of `_P_W_D' for more details.

     _._E_R_R_O_R___C_M_D
             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.

     _._E_R_R_O_R___C_W_D
             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.

     _._E_R_R_O_R___E_X_I_T
             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.

     _._E_R_R_O_R___M_E_T_A___F_I_L_E
             Is used in error handling in "meta" mode, see
             _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.

     _._E_R_R_O_R___T_A_R_G_E_T
             Is used in error handling, see _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R.

     _._I_N_C_L_U_D_E_D_F_R_O_M_D_I_R
             The directory of the file this makefile was included from.

     _._I_N_C_L_U_D_E_D_F_R_O_M_F_I_L_E
             The filename of the file this makefile was included from.

     _M_A_C_H_I_N_E
             The machine hardware name, see uname(1).

     _M_A_C_H_I_N_E___A_R_C_H
             The machine processor architecture name, see uname(1).

     _M_A_K_E    The name that bbmmaakkee was executed with (_a_r_g_v_[_0_]).

     _._M_A_K_E   The same as _M_A_K_E, for compatibility.  The preferred variable to
             use is the environment variable MAKE because it is more
             compatible with other make variants and cannot be confused with
             the special target with the same name.

     _._M_A_K_E_._D_E_P_E_N_D_F_I_L_E
             Names the makefile (default `_._d_e_p_e_n_d') from which generated
             dependencies are read.

     _._M_A_K_E_._D_I_E___Q_U_I_E_T_L_Y
             If set to `true', do not print error information at the end.

     _._M_A_K_E_._E_X_P_A_N_D___V_A_R_I_A_B_L_E_S
             A boolean that controls the default behavior of the --VV option.
             If true, variable values printed with --VV are fully expanded; if
             false, the raw variable contents (which may include additional
             unexpanded variable references) are shown.

     _._M_A_K_E_._E_X_P_O_R_T_E_D
             The list of variables exported by bbmmaakkee.

     _M_A_K_E_F_I_L_E
             The top-level makefile that is currently read, as given in the
             command line.

     _._M_A_K_E_F_L_A_G_S
             The environment variable `MAKEFLAGS' may contain anything that
             may be specified on bbmmaakkee's command line.  Anything specified on
             bbmmaakkee's command line is appended to the _._M_A_K_E_F_L_A_G_S variable,
             which is then added to the environment for all programs that
             bbmmaakkee executes.

     _._M_A_K_E_._G_I_D
             The numeric group ID of the user running bbmmaakkee.  It is read-only.

     _._M_A_K_E_._J_O_B_._P_R_E_F_I_X
             If bbmmaakkee is run with --jj, the output for each target is prefixed
             with a token
                   --- _t_a_r_g_e_t ---
             the first part of which can be controlled via _._M_A_K_E_._J_O_B_._P_R_E_F_I_X.
             If _._M_A_K_E_._J_O_B_._P_R_E_F_I_X is empty, no token is printed.  For example,
             setting _._M_A_K_E_._J_O_B_._P_R_E_F_I_X to
             `${.newline}---${.MAKE:T}[${.MAKE.PID}]' would produce tokens
             like
                   ---make[1234] _t_a_r_g_e_t ---
             making it easier to track the degree of parallelism being
             achieved.

     _._M_A_K_E_._J_O_B_S
             The argument to the --jj option.

     _._M_A_K_E_._J_O_B_S_._C
             A read-only boolean that indicates whether the --jj option supports
             use of `C'.

     _._M_A_K_E_._L_E_V_E_L
             The recursion depth of bbmmaakkee.  The top-level instance of bbmmaakkee
             has level 0, and each child make has its parent level plus 1.
             This allows tests like: .if ${.MAKE.LEVEL} == 0 to protect things
             which should only be evaluated in the top-level instance of
             bbmmaakkee.

     _._M_A_K_E_._L_E_V_E_L_._E_N_V
             The name of the environment variable that stores the level of
             nested calls to bbmmaakkee.

     _._M_A_K_E_._M_A_K_E_F_I_L_E___P_R_E_F_E_R_E_N_C_E
             The ordered list of makefile names (default `_m_a_k_e_f_i_l_e',
             `_M_a_k_e_f_i_l_e') that bbmmaakkee looks for.

     _._M_A_K_E_._M_A_K_E_F_I_L_E_S
             The list of makefiles read by bbmmaakkee, which is useful for tracking
             dependencies.  Each makefile is recorded only once, regardless of
             the number of times read.

     _._M_A_K_E_._M_E_T_A_._B_A_I_L_I_W_I_C_K
             In "meta" mode, provides a list of prefixes which match the
             directories controlled by bbmmaakkee.  If a file that was generated
             outside of _._O_B_J_D_I_R but within said bailiwick is missing, the
             current target is considered out-of-date.

     _._M_A_K_E_._M_E_T_A_._C_M_P___F_I_L_T_E_R
             In "meta" mode, it can (very rarely!) be useful to filter command
             lines before comparison.  This variable can be set to a set of
             modifiers that are applied to each line of the old and new
             command that differ, if the filtered commands still differ, the
             target is considered out-of-date.

     _._M_A_K_E_._M_E_T_A_._C_R_E_A_T_E_D
             In "meta" mode, this variable contains a list of all the meta
             files updated.  If not empty, it can be used to trigger
             processing of _._M_A_K_E_._M_E_T_A_._F_I_L_E_S.

     _._M_A_K_E_._M_E_T_A_._F_I_L_E_S
             In "meta" mode, this variable contains a list of all the meta
             files used (updated or not).  This list can be used to process
             the meta files to extract dependency information.

     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___F_I_L_T_E_R
             Provides a list of variable modifiers to apply to each pathname.
             Ignore if the expansion is an empty string.

     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_H_S
             Provides a list of path prefixes that should be ignored; because
             the contents are expected to change over time.  The default list
             includes: `_/_d_e_v _/_e_t_c _/_p_r_o_c _/_t_m_p _/_v_a_r_/_r_u_n _/_v_a_r_/_t_m_p'

     _._M_A_K_E_._M_E_T_A_._I_G_N_O_R_E___P_A_T_T_E_R_N_S
             Provides a list of patterns to match against pathnames.  Ignore
             any that match.

     _._M_A_K_E_._M_E_T_A_._P_R_E_F_I_X
             Defines the message printed for each meta file updated in "meta
             verbose" mode.  The default value is:
                   Building ${.TARGET:H:tA}/${.TARGET:T}

     _._M_A_K_E_._M_O_D_E
             Processed after reading all makefiles.  Affects the mode that
             bbmmaakkee runs in.  It can contain these keywords:

             ccoommppaatt  Like --BB, puts bbmmaakkee into "compat" mode.

             mmeettaa    Puts bbmmaakkee into "meta" mode, where meta files are created
                     for each target to capture the command run, the output
                     generated, and if filemon(4) is available, the system
                     calls which are of interest to bbmmaakkee.  The captured
                     output can be useful when diagnosing errors.

             ccuurrddiirrOOkk==_b_f
                     By default, bbmmaakkee does not create _._m_e_t_a files in
                     `_._C_U_R_D_I_R'.  This can be overridden by setting _b_f to a
                     value which represents true.

             mmiissssiinngg--mmeettaa==_b_f
                     If _b_f is true, a missing _._m_e_t_a file makes the target out-
                     of-date.

             mmiissssiinngg--ffiilleemmoonn==_b_f
                     If _b_f is true, missing filemon data makes the target out-
                     of-date.

             nnooffiilleemmoonn
                     Do not use filemon(4).

             eennvv     For debugging, it can be useful to include the
                     environment in the _._m_e_t_a file.

             vveerrbboossee
                     If in "meta" mode, print a clue about the target being
                     built.  This is useful if the build is otherwise running
                     silently.  The message printed is the expanded value of
                     _._M_A_K_E_._M_E_T_A_._P_R_E_F_I_X.

             iiggnnoorree--ccmmdd
                     Some makefiles have commands which are simply not stable.
                     This keyword causes them to be ignored for determining
                     whether a target is out of date in "meta" mode.  See also
                     ..NNOOMMEETTAA__CCMMPP.

             ssiilleenntt==_b_f
                     If _b_f is true, when a .meta file is created, mark the
                     target ..SSIILLEENNTT.

             rraannddoommiizzee--ttaarrggeettss
                     In both compat and parallel mode, do not make the targets
                     in the usual order, but instead randomize their order.
                     This mode can be used to detect undeclared dependencies
                     between files.

     _M_A_K_E_O_B_J_D_I_R
             Used to create files in a separate directory, see _._O_B_J_D_I_R.

     _M_A_K_E___O_B_J_D_I_R___C_H_E_C_K___W_R_I_T_A_B_L_E
             When true, bbmmaakkee will check that _._O_B_J_D_I_R is writable, and issue a
             warning if not.

     _M_A_K_E___D_E_B_U_G___O_B_J_D_I_R___C_H_E_C_K___W_R_I_T_A_B_L_E
             When true and bbmmaakkee is warning about an unwritable _._O_B_J_D_I_R,
             report the variables listed in _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R to help
             debug.

     _M_A_K_E_O_B_J_D_I_R_P_R_E_F_I_X
             Used to create files in a separate directory, see _._O_B_J_D_I_R.  It
             should be an absolute path.

     _._M_A_K_E_._O_S
             The name of the operating system, see uname(1).  It is read-only.

     _._M_A_K_E_O_V_E_R_R_I_D_E_S
             This variable is used to record the names of variables assigned
             to on the command line, so that they may be exported as part of
             `MAKEFLAGS'.  This behavior can be disabled by assigning an empty
             value to `_._M_A_K_E_O_V_E_R_R_I_D_E_S' within a makefile.  Extra variables can
             be exported from a makefile by appending their names to
             `_._M_A_K_E_O_V_E_R_R_I_D_E_S'.  `MAKEFLAGS' is re-exported whenever
             `_._M_A_K_E_O_V_E_R_R_I_D_E_S' is modified.

     _._M_A_K_E_._P_A_T_H___F_I_L_E_M_O_N
             If bbmmaakkee was built with filemon(4) support, this is set to the
             path of the device node.  This allows makefiles to test for this
             support.

     _._M_A_K_E_._P_I_D
             The process ID of bbmmaakkee.  It is read-only.

     _._M_A_K_E_._P_P_I_D
             The parent process ID of bbmmaakkee.  It is read-only.

     _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R
             When bbmmaakkee stops due to an error, it sets `_._E_R_R_O_R___T_A_R_G_E_T' to the
             name of the target that failed, `_._E_R_R_O_R___E_X_I_T' to the exit status
             of the failed target, `_._E_R_R_O_R___C_M_D' to the commands of the failed
             target, and in "meta" mode, it also sets `_._E_R_R_O_R___C_W_D' to the
             getcwd(3), and `_._E_R_R_O_R___M_E_T_A___F_I_L_E' to the path of the meta file
             (if any) describing the failed target.  It then prints its name
             and the value of `_._C_U_R_D_I_R' as well as the value of any variables
             named in `_M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R'.

     _._M_A_K_E_._S_A_V_E___D_O_L_L_A_R_S
             If true, `$$' are preserved when doing `:=' assignments.  The
             default is false, for backwards compatibility.  Set to true for
             compatability with other makes.  If set to false, `$$' becomes
             `$' per normal evaluation rules.

     _._M_A_K_E_._T_A_R_G_E_T___L_O_C_A_L___V_A_R_I_A_B_L_E_S
             If set to `false', apparent variable assignments in dependency
             lines are treated as normal sources.

     _._M_A_K_E_._U_I_D
             The numeric ID of the user running bbmmaakkee.  It is read-only.

     _._n_e_w_l_i_n_e
             This variable is simply assigned a newline character as its
             value.  It is read-only.  This allows expansions using the ::@@
             modifier to put a newline between iterations of the loop rather
             than a space.  For example, in case of an error, bbmmaakkee prints the
             variable names and their values using:
                   ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}

     _._O_B_J_D_I_R
             A path to the directory where the targets are built.  Its value
             is determined by trying to chdir(2) to the following directories
             in order and using the first match:

             1.   $${{MMAAKKEEOOBBJJDDIIRRPPRREEFFIIXX}}$${{..CCUURRDDIIRR}}

                  (Only if `MAKEOBJDIRPREFIX' is set in the environment or on
                  the command line.)

             2.   $${{MMAAKKEEOOBBJJDDIIRR}}

                  (Only if `MAKEOBJDIR' is set in the environment or on the
                  command line.)

             3.   $${{..CCUURRDDIIRR}}_/_o_b_j_.$${{MMAACCHHIINNEE}}

             4.   $${{..CCUURRDDIIRR}}_/_o_b_j

             5.   _/_u_s_r_/_o_b_j_/$${{..CCUURRDDIIRR}}

             6.   $${{..CCUURRDDIIRR}}

             Variable expansion is performed on the value before it is used,
             so expressions such as $${{..CCUURRDDIIRR::SS,,^^//uussrr//ssrrcc,,//vvaarr//oobbjj,,}} may be
             used.  This is especially useful with `MAKEOBJDIR'.

             `_._O_B_J_D_I_R' may be modified in the makefile via the special target
             `..OOBBJJDDIIRR'.  In all cases, bbmmaakkee changes to the specified
             directory if it exists, and sets `_._O_B_J_D_I_R' and `_P_W_D' to that
             directory before executing any targets.

             Except in the case of an explicit `..OOBBJJDDIIRR' target, bbmmaakkee checks
             that the specified directory is writable and ignores it if not.
             This check can be skipped by setting the environment variable
             `MAKE_OBJDIR_CHECK_WRITABLE' to "no".

     _._P_A_R_S_E_D_I_R
             The directory name of the current makefile being parsed.

     _._P_A_R_S_E_F_I_L_E
             The basename of the current makefile being parsed.  This variable
             and `_._P_A_R_S_E_D_I_R' are both set only while the makefiles are being
             parsed.  To retain their current values, assign them to a
             variable using assignment with expansion `::=='.

     _._P_A_T_H   The space-separated list of directories that bbmmaakkee searches for
             files.  To update this search list, use the special target
             `..PPAATTHH' rather than modifying the variable directly.

     _%_P_O_S_I_X  Is set in POSIX mode, see the special `_._P_O_S_I_X' target.

     _P_W_D     Alternate path to the current directory.  bbmmaakkee normally sets
             `_._C_U_R_D_I_R' to the canonical path given by getcwd(3).  However, if
             the environment variable `PWD' is set and gives a path to the
             current directory, bbmmaakkee sets `_._C_U_R_D_I_R' to the value of `PWD'
             instead.  This behavior is disabled if `MAKEOBJDIRPREFIX' is set
             or `MAKEOBJDIR' contains a variable transform.  `_P_W_D' is set to
             the value of `_._O_B_J_D_I_R' for all programs which bbmmaakkee executes.

     _._S_H_E_L_L  The pathname of the shell used to run target scripts.  It is
             read-only.

     _._S_U_F_F_I_X_E_S
             The list of known suffixes.  It is read-only.

     _._S_Y_S_P_A_T_H
             The space-separated list of directories that bbmmaakkee searches for
             makefiles, referred to as the system include path.  To update
             this search list, use the special target `..SSYYSSPPAATTHH' rather than
             modifying the variable which is read-only.

     _._T_A_R_G_E_T_S
             The list of targets explicitly specified on the command line, if
             any.

     _V_P_A_T_H   The colon-separated (":") list of directories that bbmmaakkee searches
             for files.  This variable is supported for compatibility with old
             make programs only, use `_._P_A_T_H' instead.

   VVaarriiaabbllee mmooddiiffiieerrss
     The general format of a variable expansion is:

           $${{_v_a_r_i_a_b_l_e[::_m_o_d_i_f_i_e_r[::...]]}}

     Each modifier begins with a colon.  To escape a colon, precede it with a
     backslash `\'.

     A list of indirect modifiers can be specified via a variable, as follows:

           _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e = _m_o_d_i_f_i_e_r[::...]

           $${{_v_a_r_i_a_b_l_e::$${{_m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e}}[::...]}}

     In this case, the first modifier in the _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e does not start
     with a colon, since that colon already occurs in the referencing
     variable.  If any of the modifiers in the _m_o_d_i_f_i_e_r___v_a_r_i_a_b_l_e contains a
     dollar sign (`$'), these must be doubled to avoid early expansion.

     Some modifiers interpret the expression value as a single string, others
     treat the expression value as a whitespace-separated list of words.  When
     splitting a string into words, whitespace can be escaped using double
     quotes, single quotes and backslashes, like in the shell.  The quotes and
     backslashes are retained in the words.

     The supported modifiers are:

     ::EE   Replaces each word with its suffix.

     ::HH   Replaces each word with its dirname.

     ::MM_p_a_t_t_e_r_n
          Selects only those words that match _p_a_t_t_e_r_n.  The standard shell
          wildcard characters (`*', `?', and `[]') may be used.  The wildcard
          characters may be escaped with a backslash (`\').  As a consequence
          of the way values are split into words, matched, and then joined,
          the construct `${VAR:M*}' removes all leading and trailing
          whitespace and normalizes the inter-word spacing to a single space.

     ::NN_p_a_t_t_e_r_n
          This is the opposite of `::MM', selecting all words which do _n_o_t match
          _p_a_t_t_e_r_n.

     ::OO   Orders the words lexicographically.

     ::OOnn  Orders the words numerically.  A number followed by one of `k', `M'
          or `G' is multiplied by the appropriate factor, which is 1024 for
          `k', 1048576 for `M', or 1073741824 for `G'.  Both upper- and lower-
          case letters are accepted.

     ::OOrr  Orders the words in reverse lexicographical order.

     ::OOrrnn
          Orders the words in reverse numerical order.

     ::OOxx  Shuffles the words.  The results are different each time you are
          referring to the modified variable; use the assignment with
          expansion `::==' to prevent such behavior.  For example,

                LIST=                   uno due tre quattro
                RANDOM_LIST=            ${LIST:Ox}
                STATIC_RANDOM_LIST:=    ${LIST:Ox}

                all:
                        @echo "${RANDOM_LIST}"
                        @echo "${RANDOM_LIST}"
                        @echo "${STATIC_RANDOM_LIST}"
                        @echo "${STATIC_RANDOM_LIST}"
          may produce output similar to:

                quattro due tre uno
                tre due quattro uno
                due uno quattro tre
                due uno quattro tre

     ::QQ   Quotes every shell meta-character in the value, so that it can be
          passed safely to the shell.

     ::qq   Quotes every shell meta-character in the value, and also doubles `$'
          characters so that it can be passed safely through recursive
          invocations of bbmmaakkee.  This is equivalent to `::SS//\\$$//&&&&//gg::QQ'.

     ::RR   Replaces each word with everything but its suffix.

     ::rraannggee[==_c_o_u_n_t]
          The value is an integer sequence representing the words of the
          original value, or the supplied _c_o_u_n_t.

     ::ggmmttiimmee[==_t_i_m_e_s_t_a_m_p]
          The value is interpreted as a format string for strftime(3), using
          gmtime(3), producing the formatted timestamp.  Note: the `%s' format
          should only be used with `::llooccaallttiimmee'.  If a _t_i_m_e_s_t_a_m_p value is not
          provided or is 0, the current time is used.

     ::hhaasshh
          Computes a 32-bit hash of the value and encodes it as 8 hex digits.

     ::llooccaallttiimmee[==_t_i_m_e_s_t_a_m_p]
          The value is interpreted as a format string for strftime(3), using
          localtime(3), producing the formatted timestamp.  If a _t_i_m_e_s_t_a_m_p
          value is not provided or is 0, the current time is used.

     ::mmttiimmee[==_t_i_m_e_s_t_a_m_p]
          Call stat(2) with each word as pathname; use `st_mtime' as the new
          value.  If stat(2) fails; use _t_i_m_e_s_t_a_m_p or current time.  If
          _t_i_m_e_s_t_a_m_p is set to `error', then stat(2) failure will cause an
          error.

     ::ttAA  Attempts to convert the value to an absolute path using realpath(3).
          If that fails, the value is unchanged.

     ::ttll  Converts the value to lower-case letters.

     ::ttss_c
          When joining the words after a modifier that treats the value as
          words, the words are normally separated by a space.  This modifier
          changes the separator to the character _c.  If _c is omitted, no
          separator is used.  The common escapes (including octal numeric
          codes) work as expected.

     ::tttt  Converts the first character of each word to upper-case, and the
          rest to lower-case letters.

     ::ttuu  Converts the value to upper-case letters.

     ::ttWW  Causes subsequent modifiers to treat the value as a single word
          (possibly containing embedded whitespace).  See also `::[[**]]'.

     ::ttww  Causes the value to be treated as a list of words.  See also `::[[@@]]'.

     ::SS/_o_l_d___s_t_r_i_n_g/_n_e_w___s_t_r_i_n_g/[11ggWW]
          Modifies the first occurrence of _o_l_d___s_t_r_i_n_g in each word of the
          value, replacing it with _n_e_w___s_t_r_i_n_g.  If a `g' is appended to the
          last delimiter of the pattern, all occurrences in each word are
          replaced.  If a `1' is appended to the last delimiter of the
          pattern, only the first occurrence is affected.  If a `W' is
          appended to the last delimiter of the pattern, the value is treated
          as a single word.  If _o_l_d___s_t_r_i_n_g begins with a caret (`^'),
          _o_l_d___s_t_r_i_n_g is anchored at the beginning of each word.  If _o_l_d___s_t_r_i_n_g
          ends with a dollar sign (`$'), it is anchored at the end of each
          word.  Inside _n_e_w___s_t_r_i_n_g, an ampersand (`&') is replaced by
          _o_l_d___s_t_r_i_n_g (without the anchoring `^' or `$').  Any character may be
          used as the delimiter for the parts of the modifier string.  The
          anchoring, ampersand and delimiter characters can be escaped with a
          backslash (`\').

          Both _o_l_d___s_t_r_i_n_g and _n_e_w___s_t_r_i_n_g may contain nested expressions.  To
          prevent a dollar sign from starting a nested expression, escape it
          with a backslash.

     ::CC/_p_a_t_t_e_r_n/_r_e_p_l_a_c_e_m_e_n_t/[11ggWW]
          The ::CC modifier works like the ::SS modifier except that the old and
          new strings, instead of being simple strings, are an extended
          regular expression _p_a_t_t_e_r_n (see regex(3)) and an ed(1)-style
          _r_e_p_l_a_c_e_m_e_n_t.  Normally, the first occurrence of the pattern _p_a_t_t_e_r_n
          in each word of the value is substituted with _r_e_p_l_a_c_e_m_e_n_t.  The `1'
          modifier causes the substitution to apply to at most one word; the
          `g' modifier causes the substitution to apply to as many instances
          of the search pattern _p_a_t_t_e_r_n as occur in the word or words it is
          found in; the `W' modifier causes the value to be treated as a
          single word (possibly containing embedded whitespace).

          As for the ::SS modifier, the _p_a_t_t_e_r_n and _r_e_p_l_a_c_e_m_e_n_t are subjected to
          variable expansion before being parsed as regular expressions.

     ::TT   Replaces each word with its last path component (basename).

     ::uu   Removes adjacent duplicate words (like uniq(1)).

     ::??_t_r_u_e___s_t_r_i_n_g::_f_a_l_s_e___s_t_r_i_n_g
          If the variable name (not its value), when parsed as a ..iiff
          conditional expression, evaluates to true, return as its value the
          _t_r_u_e___s_t_r_i_n_g, otherwise return the _f_a_l_s_e___s_t_r_i_n_g.  Since the variable
          name is used as the expression, :? must be the first modifier after
          the variable name itself--which, of course, usually contains
          variable expansions.  A common error is trying to use expressions
          like
                ${NUMBERS:M42:?match:no}
          which actually tests defined(NUMBERS).  To determine if any words
          match "42", you need to use something like:
                ${"${NUMBERS:M42}" != "":?match:no}.

     ::_o_l_d___s_t_r_i_n_g==_n_e_w___s_t_r_i_n_g
          This is the AT&T System V UNIX style substitution.  It can only be
          the last modifier specified, as a `:' in either _o_l_d___s_t_r_i_n_g or
          _n_e_w___s_t_r_i_n_g is treated as a regular character, not as the end of the
          modifier.

          If _o_l_d___s_t_r_i_n_g does not contain the pattern matching character `%',
          and the word ends with _o_l_d___s_t_r_i_n_g or equals it, that suffix is
          replaced with _n_e_w___s_t_r_i_n_g.

          Otherwise, the first `%' in _o_l_d___s_t_r_i_n_g matches a possibly empty
          substring of arbitrary characters, and if the whole pattern is found
          in the word, the matching part is replaced with _n_e_w___s_t_r_i_n_g, and the
          first occurrence of `%' in _n_e_w___s_t_r_i_n_g (if any) is replaced with the
          substring matched by the `%'.

          Both _o_l_d___s_t_r_i_n_g and _n_e_w___s_t_r_i_n_g may contain nested expressions.  To
          prevent a dollar sign from starting a nested expression, escape it
          with a backslash.

     ::@@_v_a_r_n_a_m_e@@_s_t_r_i_n_g@@
          This is the loop expansion mechanism from the OSF Development
          Environment (ODE) make.  Unlike ..ffoorr loops, expansion occurs at the
          time of reference.  For each word in the value, assign the word to
          the variable named _v_a_r_n_a_m_e and evaluate _s_t_r_i_n_g.  The ODE convention
          is that _v_a_r_n_a_m_e should start and end with a period, for example:
                ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}

          However, a single-letter variable is often more readable:
                ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}

     ::__[==_v_a_r]
          Saves the current variable value in `$_' or the named _v_a_r for later
          reference.  Example usage:

                M_cmpv.units = 1 1000 1000000
                M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \
                \* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh

                .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}

          Here `$_' is used to save the result of the `:S' modifier which is
          later referenced using the index values from `:range'.

     ::UU_n_e_w_v_a_l
          If the variable is undefined, the optional _n_e_w_v_a_l (which may be
          empty) is the value.  If the variable is defined, the existing value
          is returned.  This is another ODE make feature.  It is handy for
          setting per-target CFLAGS for instance:
                ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
          If a value is only required if the variable is undefined, use:
                ${VAR:D:Unewval}

     ::DD_n_e_w_v_a_l
          If the variable is defined, _n_e_w_v_a_l (which may be empty) is the
          value.

     ::LL   The name of the variable is the value.

     ::PP   The path of the node which has the same name as the variable is the
          value.  If no such node exists or its path is null, the name of the
          variable is used.  In order for this modifier to work, the name
          (node) must at least have appeared on the right-hand side of a
          dependency.

     ::!!_c_m_d!!
          The output of running _c_m_d is the value.

     ::sshh  The value is run as a command, and the output becomes the new value.

     ::::==_s_t_r
          The variable is assigned the value _s_t_r after substitution.  This
          modifier and its variations are useful in obscure situations such as
          wanting to set a variable at a point where a target's shell commands
          are being parsed.  These assignment modifiers always expand to
          nothing.

          The `::::' helps avoid false matches with the AT&T System V UNIX style
          `:=' modifier and since substitution always occurs, the `::=' form
          is vaguely appropriate.

     ::::??==_s_t_r
          As for ::::== but only if the variable does not already have a value.

     ::::++==_s_t_r
          Append _s_t_r to the variable.

     ::::!!==_c_m_d
          Assign the output of _c_m_d to the variable.

     ::[[_r_a_n_g_e]]
          Selects one or more words from the value, or performs other
          operations related to the way in which the value is split into
          words.

          An empty value, or a value that consists entirely of white-space, is
          treated as a single word.  For the purposes of the `::[[]]' modifier,
          the words are indexed both forwards using positive integers (where
          index 1 represents the first word), and backwards using negative
          integers (where index -1 represents the last word).

          The _r_a_n_g_e is subjected to variable expansion, and the expanded
          result is then interpreted as follows:

          _i_n_d_e_x  Selects a single word from the value.

          _s_t_a_r_t...._e_n_d
                 Selects all words from _s_t_a_r_t to _e_n_d, inclusive.  For example,
                 `::[[22....--11]]' selects all words from the second word to the last
                 word.  If _s_t_a_r_t is greater than _e_n_d, the words are output in
                 reverse order.  For example, `::[[--11....11]]' selects all the words
                 from last to first.  If the list is already ordered, this
                 effectively reverses the list, but it is more efficient to
                 use `::OOrr' instead of `::OO::[[--11....11]]'.

          **      Causes subsequent modifiers to treat the value as a single
                 word (possibly containing embedded whitespace).  Analogous to
                 the effect of $* in Bourne shell.

          0      Means the same as `::[[**]]'.

          @@      Causes subsequent modifiers to treat the value as a sequence
                 of words delimited by whitespace.  Analogous to the effect of
                 $@ in Bourne shell.

          ##      Returns the number of words in the value.

DDIIRREECCTTIIVVEESS
     bbmmaakkee offers directives for including makefiles, conditionals and for
     loops.  All these directives are identified by a line beginning with a
     single dot (`.') character, followed by the keyword of the directive,
     such as iinncclluuddee or iiff.

   FFiillee iinncclluussiioonn
     Files are included with either ..iinncclluuddee <<_f_i_l_e>> or ..iinncclluuddee ""_f_i_l_e"".
     Variables between the angle brackets or double quotes are expanded to
     form the file name.  If angle brackets are used, the included makefile is
     expected to be in the system makefile directory.  If double quotes are
     used, the including makefile's directory and any directories specified
     using the --II option are searched before the system makefile directory.

     For compatibility with other make variants, `iinncclluuddee _f_i_l_e ...' (without
     leading dot) is also accepted.

     If the include statement is written as ..--iinncclluuddee or as ..ssiinncclluuddee, errors
     locating and/or opening include files are ignored.

     If the include statement is written as ..ddiinncclluuddee, not only are errors
     locating and/or opening include files ignored, but stale dependencies
     within the included file are ignored just like in _._M_A_K_E_._D_E_P_E_N_D_F_I_L_E.

   EExxppoorrttiinngg vvaarriiaabblleess
     The directives for exporting and unexporting variables are:

     ..eexxppoorrtt _v_a_r_i_a_b_l_e ...
             Export the specified global variable.

             For compatibility with other make programs, eexxppoorrtt _v_a_r_i_a_b_l_e==_v_a_l_u_e
             (without leading dot) is also accepted.

             Appending a variable name to _._M_A_K_E_._E_X_P_O_R_T_E_D is equivalent to
             exporting a variable.

     ..eexxppoorrtt--aallll
             Export all globals except for internal variables (those that
             start with `.').  This is not affected by the --XX flag, so should
             be used with caution.

     ..eexxppoorrtt--eennvv _v_a_r_i_a_b_l_e ...
             The same as `.export', except that the variable is not appended
             to _._M_A_K_E_._E_X_P_O_R_T_E_D.  This allows exporting a value to the
             environment which is different from that used by bbmmaakkee
             internally.

     ..eexxppoorrtt--lliitteerraall _v_a_r_i_a_b_l_e ...
             The same as `.export-env', except that variables in the value are
             not expanded.

     ..uunneexxppoorrtt _v_a_r_i_a_b_l_e ...
             The opposite of `.export'.  The specified global _v_a_r_i_a_b_l_e is
             removed from _._M_A_K_E_._E_X_P_O_R_T_E_D.  If no variable list is provided,
             all globals are unexported, and _._M_A_K_E_._E_X_P_O_R_T_E_D deleted.

     ..uunneexxppoorrtt--eennvv
             Unexport all globals previously exported and clear the
             environment inherited from the parent.  This operation causes a
             memory leak of the original environment, so should be used
             sparingly.  Testing for _._M_A_K_E_._L_E_V_E_L being 0 would make sense.
             Also note that any variables which originated in the parent
             environment should be explicitly preserved if desired.  For
             example:

                   .if ${.MAKE.LEVEL} == 0
                   PATH := ${PATH}
                   .unexport-env
                   .export PATH
                   .endif

             Would result in an environment containing only `PATH', which is
             the minimal useful environment.  Actually `_._M_A_K_E_._L_E_V_E_L' is also
             pushed into the new environment.

   MMeessssaaggeess
     The directives for printing messages to the output are:

     ..iinnffoo _m_e_s_s_a_g_e
             The message is printed along with the name of the makefile and
             line number.

     ..wwaarrnniinngg _m_e_s_s_a_g_e
             The message prefixed by `warning:' is printed along with the name
             of the makefile and line number.

     ..eerrrroorr _m_e_s_s_a_g_e
             The message is printed along with the name of the makefile and
             line number, bbmmaakkee exits immediately.

   CCoonnddiittiioonnaallss
     The directives for conditionals are:

     ..iiff [!!]_e_x_p_r_e_s_s_i_o_n [_o_p_e_r_a_t_o_r _e_x_p_r_e_s_s_i_o_n ...]
             Test the value of an expression.

     ..iiffddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
             Test whether a variable is defined.

     ..iiffnnddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
             Test whether a variable is not defined.

     ..iiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
             Test the target being requested.

     ..iiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
             Test the target being requested.

     ..eellssee   Reverse the sense of the last conditional.

     ..eelliiff [!!]_e_x_p_r_e_s_s_i_o_n [_o_p_e_r_a_t_o_r _e_x_p_r_e_s_s_i_o_n ...]
             A combination of `..eellssee' followed by `..iiff'.

     ..eelliiffddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
             A combination of `..eellssee' followed by `..iiffddeeff'.

     ..eelliiffnnddeeff [!!]_v_a_r_i_a_b_l_e [_o_p_e_r_a_t_o_r _v_a_r_i_a_b_l_e ...]
             A combination of `..eellssee' followed by `..iiffnnddeeff'.

     ..eelliiffmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
             A combination of `..eellssee' followed by `..iiffmmaakkee'.

     ..eelliiffnnmmaakkee [!!]_t_a_r_g_e_t [_o_p_e_r_a_t_o_r _t_a_r_g_e_t ...]
             A combination of `..eellssee' followed by `..iiffnnmmaakkee'.

     ..eennddiiff  End the body of the conditional.

     The _o_p_e_r_a_t_o_r may be any one of the following:

     ||||      Logical OR.

     &&&&      Logical AND; of higher precedence than `||||'.

     bbmmaakkee only evaluates a conditional as far as is necessary to determine
     its value.  Parentheses can be used to override the operator precedence.
     The boolean operator `!!' may be used to logically negate an expression,
     typically a function call.  It is of higher precedence than `&&&&'.

     The value of _e_x_p_r_e_s_s_i_o_n may be any of the following function call
     expressions:

     ddeeffiinneedd(_v_a_r_n_a_m_e)
             Evaluates to true if the variable _v_a_r_n_a_m_e has been defined.

     mmaakkee(_t_a_r_g_e_t)
             Evaluates to true if the target was specified as part of bbmmaakkee's
             command line or was declared the default target (either
             implicitly or explicitly, see _._M_A_I_N) before the line containing
             the conditional.

     eemmppttyy(_v_a_r_n_a_m_e[:_m_o_d_i_f_i_e_r_s])
             Evaluates to true if the expansion of the variable, after
             applying the modifiers, results in an empty string.

     eexxiissttss(_p_a_t_h_n_a_m_e)
             Evaluates to true if the given pathname exists.  If relative, the
             pathname is searched for on the system search path (see _._P_A_T_H).

     ttaarrggeett(_t_a_r_g_e_t)
             Evaluates to true if the target has been defined.

     ccoommmmaannddss(_t_a_r_g_e_t)
             Evaluates to true if the target has been defined and has commands
             associated with it.

     _E_x_p_r_e_s_s_i_o_n may also be an arithmetic or string comparison.  Variable
     expansion is performed on both sides of the comparison.  If both sides
     are numeric and neither is enclosed in quotes, the comparison is done
     numerically, otherwise lexicographically.  A string is interpreted as a
     hexadecimal integer if it is preceded by 0x, otherwise it is interpreted
     as a decimal floating-point number; octal numbers are not supported.

     All comparisons may use the operators `====' and `!!=='.  Numeric comparisons
     may also use the operators `<<', `<<==', `>>' and `>>=='.

     If the comparison has neither a comparison operator nor a right side, the
     expression evaluates to true if it is nonempty and its numeric value (if
     any) is not zero.

     When bbmmaakkee is evaluating one of these conditional expressions, and it
     encounters a (whitespace-separated) word it doesn't recognize, either the
     "make" or "defined" function is applied to it, depending on the form of
     the conditional.  If the form is `..iiffddeeff', `..iiffnnddeeff' or `..iiff', the
     "defined" function is applied.  Similarly, if the form is `..iiffmmaakkee' or
     `..iiffnnmmaakkee', the "make" function is applied.

     If the conditional evaluates to true, parsing of the makefile continues
     as before.  If it evaluates to false, the following lines until the
     corresponding `..eelliiff' variant, `..eellssee' or `..eennddiiff' are skipped.

   FFoorr llooooppss
     For loops are typically used to apply a set of rules to a list of files.
     The syntax of a for loop is:

     ..ffoorr _v_a_r_i_a_b_l_e [_v_a_r_i_a_b_l_e ...] iinn _e_x_p_r_e_s_s_i_o_n
     <_m_a_k_e_-_l_i_n_e_s>
     ..eennddffoorr

     The _e_x_p_r_e_s_s_i_o_n is expanded and then split into words.  On each iteration
     of the loop, one word is taken and assigned to each _v_a_r_i_a_b_l_e, in order,
     and these _v_a_r_i_a_b_l_e_s are substituted into the _m_a_k_e_-_l_i_n_e_s inside the body
     of the for loop.  The number of words must come out even; that is, if
     there are three iteration variables, the number of words provided must be
     a multiple of three.

     If `..bbrreeaakk' is encountered within a ..ffoorr loop, it causes early
     termination of the loop, otherwise a parse error.

   OOtthheerr ddiirreeccttiivveess
     ..uunnddeeff _v_a_r_i_a_b_l_e ...
             Un-define the specified global variables.  Only global variables
             can be un-defined.

CCOOMMMMEENNTTSS
     Comments begin with a hash (`#') character, anywhere but in a shell
     command line, and continue to the end of an unescaped new line.

SSPPEECCIIAALL SSOOUURRCCEESS ((AATTTTRRIIBBUUTTEESS))
     ..EEXXEECC     Target is never out of date, but always execute commands
               anyway.

     ..IIGGNNOORREE   Ignore any errors from the commands associated with this
               target, exactly as if they all were preceded by a dash (`-').

     ..MMAADDEE     Mark all sources of this target as being up to date.

     ..MMAAKKEE     Execute the commands associated with this target even if the --nn
               or --tt options were specified.  Normally used to mark recursive
               bbmmaakkees.

     ..MMEETTAA     Create a meta file for the target, even if it is flagged as
               ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL.  Usage in conjunction with ..MMAAKKEE is
               the most likely case.  In "meta" mode, the target is out-of-
               date if the meta file is missing.

     ..NNOOMMEETTAA   Do not create a meta file for the target.  Meta files are also
               not created for ..PPHHOONNYY, ..MMAAKKEE, or ..SSPPEECCIIAALL targets.

     ..NNOOMMEETTAA__CCMMPP
               Ignore differences in commands when deciding if target is out
               of date.  This is useful if the command contains a value which
               always changes.  If the number of commands change, though, the
               target is still considered out of date.  The same effect
               applies to any command line that uses the variable _._O_O_D_A_T_E,
               which can be used for that purpose even when not otherwise
               needed or desired:


                     skip-compare-for-some:
                             @echo this is compared
                             @echo this is not ${.OODATE:M.NOMETA_CMP}
                             @echo this is also compared

               The ::MM pattern suppresses any expansion of the unwanted
               variable.

     ..NNOOPPAATTHH   Do not search for the target in the directories specified by
               _._P_A_T_H.

     ..NNOOTTMMAAIINN  Normally bbmmaakkee selects the first target it encounters as the
               default target to be built if no target was specified.  This
               source prevents this target from being selected.

     ..OOPPTTIIOONNAALL
               If a target is marked with this attribute and bbmmaakkee can't
               figure out how to create it, it ignores this fact and assumes
               the file isn't needed or already exists.

     ..PPHHOONNYY    The target does not correspond to an actual file; it is always
               considered to be out of date, and is not created with the --tt
               option.  Suffix-transformation rules are not applied to ..PPHHOONNYY
               targets.

     ..PPRREECCIIOOUUSS
               When bbmmaakkee is interrupted, it normally removes any partially
               made targets.  This source prevents the target from being
               removed.

     ..RREECCUURRSSIIVVEE
               Synonym for ..MMAAKKEE.

     ..SSIILLEENNTT   Do not echo any of the commands associated with this target,
               exactly as if they all were preceded by an at sign (`@').

     ..UUSSEE      Turn the target into bbmmaakkee's version of a macro.  When the
               target is used as a source for another target, the other target
               acquires the commands, sources, and attributes (except for
               ..UUSSEE) of the source.  If the target already has commands, the
               ..UUSSEE target's commands are appended to them.

     ..UUSSEEBBEEFFOORREE
               Like ..UUSSEE, but instead of appending, prepend the ..UUSSEEBBEEFFOORREE
               target commands to the target.

     ..WWAAIITT     If ..WWAAIITT appears in a dependency line, the sources that precede
               it are made before the sources that succeed it in the line.
               Since the dependents of files are not made until the file
               itself could be made, this also stops the dependents being
               built unless they are needed for another branch of the
               dependency tree.  So given:

               x: a .WAIT b
                       echo x
               a:
                       echo a
               b: b1
                       echo b
               b1:
                       echo b1

               the output is always `a', `b1', `b', `x'.

               The ordering imposed by ..WWAAIITT is only relevant for parallel
               makes.

SSPPEECCIIAALL TTAARRGGEETTSS
     Special targets may not be included with other targets, i.e. they must be
     the only target specified.

     ..BBEEGGIINN   Any command lines attached to this target are executed before
              anything else is done.

     ..DDEEFFAAUULLTT
              This is sort of a ..UUSSEE rule for any target (that was used only
              as a source) that bbmmaakkee can't figure out any other way to
              create.  Only the shell script is used.  The _._I_M_P_S_R_C variable of
              a target that inherits ..DDEEFFAAUULLTT's commands is set to the
              target's own name.

     ..DDEELLEETTEE__OONN__EERRRROORR
              If this target is present in the makefile, it globally causes
              make to delete targets whose commands fail.  (By default, only
              targets whose commands are interrupted during execution are
              deleted.  This is the historical behavior.)  This setting can be
              used to help prevent half-finished or malformed targets from
              being left around and corrupting future rebuilds.

     ..EENNDD     Any command lines attached to this target are executed after
              everything else is done successfully.

     ..EERRRROORR   Any command lines attached to this target are executed when
              another target fails.  See _M_A_K_E___P_R_I_N_T___V_A_R___O_N___E_R_R_O_R for the
              variables that will be set.

     ..IIGGNNOORREE  Mark each of the sources with the ..IIGGNNOORREE attribute.  If no
              sources are specified, this is the equivalent of specifying the
              --ii option.

     ..IINNTTEERRRRUUPPTT
              If bbmmaakkee is interrupted, the commands for this target are
              executed.

     ..MMAAIINN    If no target is specified when bbmmaakkee is invoked, this target is
              built.

     ..MMAAKKEEFFLLAAGGSS
              This target provides a way to specify flags for bbmmaakkee at the
              time when the makefiles are read.  The flags are as if typed to
              the shell, though the --ff option has no effect.

     ..NNOOPPAATTHH  Apply the ..NNOOPPAATTHH attribute to any specified sources.

     ..NNOOTTPPAARRAALLLLEELL
              Disable parallel mode.

     ..NNOO__PPAARRAALLLLEELL
              Synonym for ..NNOOTTPPAARRAALLLLEELL, for compatibility with other pmake
              variants.

     ..NNOORREEAADDOONNLLYY
              clear the read-only attribute from the global variables
              specified as sources.

     ..OOBBJJDDIIRR  The source is a new value for `_._O_B_J_D_I_R'.  If it exists, bbmmaakkee
              changes the current working directory to it and updates the
              value of `_._O_B_J_D_I_R'.

     ..OORRDDEERR   In parallel mode, the named targets are made in sequence.  This
              ordering does not add targets to the list of targets to be made.

              Since the dependents of a target do not get built until the
              target itself could be built, unless `a' is built by another
              part of the dependency graph, the following is a dependency
              loop:

              .ORDER: b a
              b: a

     ..PPAATTHH    The sources are directories which are to be searched for files
              not found in the current directory.  If no sources are
              specified, any previously specified directories are removed from
              the search path.  If the source is the special ..DDOOTTLLAASSTT target,
              the current working directory is searched last.

     ..PPAATTHH.._s_u_f_f_i_x
              Like ..PPAATTHH but applies only to files with a particular suffix.
              The suffix must have been previously declared with ..SSUUFFFFIIXXEESS.

     ..PPHHOONNYY   Apply the ..PPHHOONNYY attribute to any specified sources.

     ..PPOOSSIIXX   If this is the first non-comment line in the main makefile, the
              variable _%_P_O_S_I_X is set to the value `1003.2' and the makefile
              `<posix.mk>' is included if it exists, to provide POSIX-
              compatible default rules.  If bbmmaakkee is run with the --rr flag,
              only `posix.mk' contributes to the default rules.

     ..PPRREECCIIOOUUSS
              Apply the ..PPRREECCIIOOUUSS attribute to any specified sources.  If no
              sources are specified, the ..PPRREECCIIOOUUSS attribute is applied to
              every target in the file.

     ..RREEAADDOONNLLYY
              set the read-only attribute on the global variables specified as
              sources.

     ..SSHHEELLLL   Sets the shell that bbmmaakkee uses to execute commands.  The sources
              are a set of _f_i_e_l_d==_v_a_l_u_e pairs.

              name        This is the minimal specification, used to select
                          one of the built-in shell specs; sh, ksh, and csh.

              path        Specifies the absolute path to the shell.

              hasErrCtl   Indicates whether the shell supports exit on error.

              check       The command to turn on error checking.

              ignore      The command to disable error checking.

              echo        The command to turn on echoing of commands executed.

              quiet       The command to turn off echoing of commands
                          executed.

              filter      The output to filter after issuing the quiet
                          command.  It is typically identical to quiet.

              errFlag     The flag to pass the shell to enable error checking.

              echoFlag    The flag to pass the shell to enable command
                          echoing.

              newline     The string literal to pass the shell that results in
                          a single newline character when used outside of any
                          quoting characters.
              Example:

              .SHELL: name=ksh path=/bin/ksh hasErrCtl=true \
                      check="set -e" ignore="set +e" \
                      echo="set -v" quiet="set +v" filter="set +v" \
                      echoFlag=v errFlag=e newline="'\n'"

     ..SSIILLEENNTT  Apply the ..SSIILLEENNTT attribute to any specified sources.  If no
              sources are specified, the ..SSIILLEENNTT attribute is applied to every
              command in the file.

     ..SSTTAALLEE   This target gets run when a dependency file contains stale
              entries, having _._A_L_L_S_R_C set to the name of that dependency file.

     ..SSUUFFFFIIXXEESS
              Each source specifies a suffix to bbmmaakkee.  If no sources are
              specified, any previously specified suffixes are deleted.  It
              allows the creation of suffix-transformation rules.

              Example:

              .SUFFIXES: .c .o
              .c.o:
                      cc -o ${.TARGET} -c ${.IMPSRC}

     ..SSYYSSPPAATTHH
              The sources are directories which are to be added to the system
              include path which bbmmaakkee searches for makefiles.  If no sources
              are specified, any previously specified directories are removed
              from the system include path.

EENNVVIIRROONNMMEENNTT
     bbmmaakkee uses the following environment variables, if they exist: MACHINE,
     MACHINE_ARCH, MAKE, MAKEFLAGS, MAKEOBJDIR, MAKEOBJDIRPREFIX, MAKESYSPATH,
     PWD, and TMPDIR.

     MAKEOBJDIRPREFIX and MAKEOBJDIR should be set in the environment or on
     the command line to bbmmaakkee and not as makefile variables; see the
     description of `_._O_B_J_D_I_R' for more details.  It is possible to set these
     via makefile variables but unless done very early and the `..OOBBJJDDIIRR'
     target is used to reset `_._O_B_J_D_I_R', there may be unexpected side effects.

FFIILLEESS
     .depend        list of dependencies
     makefile       first default makefile if no makefile is specified on the
                    command line
     Makefile       second default makefile if no makefile is specified on the
                    command line
     sys.mk         system makefile
     /usr/share/mk  system makefile directory

CCOOMMPPAATTIIBBIILLIITTYY
     The basic make syntax is compatible between different make variants;
     however the special variables, variable modifiers and conditionals are
     not.

   OOllddeerr vveerrssiioonnss
     An incomplete list of changes in older versions of bbmmaakkee:

     The way that .for loop variables are substituted changed after NetBSD 5.0
     so that they still appear to be variable expansions.  In particular this
     stops them being treated as syntax, and removes some obscure problems
     using them in .if statements.

     The way that parallel makes are scheduled changed in NetBSD 4.0 so that
     .ORDER and .WAIT apply recursively to the dependent nodes.  The
     algorithms used may change again in the future.

   OOtthheerr mmaakkee ddiiaalleeccttss
     Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
     support most of the features of bbmmaakkee as described in this manual.  Most
     notably:

           ++oo   The ..WWAAIITT and ..OORRDDEERR declarations and most functionality
               pertaining to parallelization.  (GNU make supports
               parallelization but lacks the features needed to control it
               effectively.)

           ++oo   Directives, including for loops and conditionals and most of
               the forms of include files.  (GNU make has its own incompatible
               and less powerful syntax for conditionals.)

           ++oo   All built-in variables that begin with a dot.

           ++oo   Most of the special sources and targets that begin with a dot,
               with the notable exception of ..PPHHOONNYY, ..PPRREECCIIOOUUSS, and ..SSUUFFFFIIXXEESS.

           ++oo   Variable modifiers, except for the `:old=new' string
               substitution, which does not portably support globbing with `%'
               and historically only works on declared suffixes.

           ++oo   The $$>> variable even in its short form; most makes support this
               functionality but its name varies.

     Some features are somewhat more portable, such as assignment with ++==, ??==,
     and !!==.  The _._P_A_T_H functionality is based on an older feature VVPPAATTHH found
     in GNU make and many versions of SVR4 make; however, historically its
     behavior is too ill-defined (and too buggy) to rely upon.

     The $$@@ and $$<< variables are more or less universally portable, as is the
     $$((MMAAKKEE)) variable.  Basic use of suffix rules (for files only in the
     current directory, not trying to chain transformations together, etc.) is
     also reasonably portable.

SSEEEE AALLSSOO
     mkdep(1)

HHIISSTTOORRYY
     bbmmaakkee is derived from NetBSD make(1).  It uses autoconf to facilitate
     portability to other platforms.

     A make command appeared in Version 7 AT&T UNIX.  This make implementation
     is based on Adam de Boor's pmake program, which was written for Sprite at
     Berkeley.  It was designed to be a parallel distributed make running jobs
     on different machines using a daemon called "customs".

     Historically the target/dependency FFRRCC has been used to FoRCe rebuilding
     (since the target/dependency does not exist ... unless someone creates an
     _F_R_C file).

BBUUGGSS
     The bbmmaakkee syntax is difficult to parse.  For instance, finding the end of
     a variable's use should involve scanning each of the modifiers, using the
     correct terminator for each field.  In many places bbmmaakkee just counts {}
     and () in order to find the end of a variable expansion.

     There is no way of escaping a space character in a filename.

     In jobs mode, when a target fails; bbmmaakkee will put an error token into the
     job token pool.  This will cause all other instances of bbmmaakkee using that
     token pool to abort the build and exit with error code 6.  Sometimes the
     attempt to suppress a cascade of unnecessary errors, can result in a
     seemingly unexplained `*** Error code 6'

FreeBSD 14.1-RELEASE-p7        November 14, 2024       FreeBSD 14.1-RELEASE-p7