This update fixes a few bugs:
- Improper response to double SIGINT with editline.
- Not letting libedit handle terminal size changes.
- A dc crash from improperly handling an error.
- A duplicate check for reference arrays.
- Build failures with GCC 15.

This update fixes a potential issue when flushing stdout on exit
fails: longjmp could use an uninitialized target address variable.

Most files are included in this commit due to a changed date in
the copyright note.

This update fixes a bug that line breaks in printed numbers may not
match the line length set by the user. The value is printed correctly,
just not split as specified in some situations.

This update removes printing of a leading zero in scientific or
engineering output modes (which are an extended feature of this
implementation).

This is a production release with a new feature and a few bug fixes.

The bug fixes include:

 - A crash when bc and dc are built using editline, but history is not
   activated.
 - A missing local in the uint*() family of functions in the extended
   math library.
 - A failure to clear the tail call list in dc on error.
 - A crash when attempting to swap characters in command-line history
   when no characters exist.
 - SIGWINCH was activated even when history was not.

The new feature is that stack traces are now given for runtime errors.
In debug mode, the C source file and line of errors are given as well.

Changes relative to the previous version in FreeBSD:

- Fix error message on certain syntax errors.
- Add digit clamping (build option and run-time option)
- Make -l options no longer overridee scale value set with -S

This version adds support for command line editing and history using
the editline or readline libraries in addition to the line editing
features available in previous versions.

This is a new major release with a number of changes and extensions:

- Limited the number of temporary numbers and made the space for them
  static so that allocating more space for them cannot fail.
- Allowed integers with non-zero scale to be used with power, places,
  and shift operators.
- Added greatest common divisor and least common multiple to lib2.bc.
- Made bc and dc UTF-8 capable.
- Added the ability for users to have bc and dc quit on SIGINT.
- Added the ability for users to disable prompt and TTY mode by
  environment variables.
- Added the ability for users to redefine keywords.
- Added dc's modular exponentiation and divmod to bc.
- Added the ability to assign strings to variables and array elements
  and pass them to functions in bc.
- Added dc's asciify command and stream printing to bc.
- Added bitwise and, or, xor, left shift, right shift, reverse,
  left rotate, right rotate, and mod functions to lib2.bc.
- Added the functions s2u(x) and s2un(x,n), to lib2.bc.