'RELENG_3_3_0_RELEASE'.

This commit was manufactured to restore the state of the 3.3-RELEASE image.
Releases prior to 5.3-RELEASE are omitting the secure/ and crypto/ subdirs.

descriptors are not opened.

PR:		bin/12853

(addition of wrapped poll).

This should fix MySQL problems.

kill (signal) it.

Submitted by: Steve Bernacki, Jr. <steve@navinet.net>

the thread kernel into a garbage collector thread which is started when
the fisrt thread is created (other than the initial thread). This
removes the window of opportunity where a context switch will cause a
thread that has locked the malloc spinlock, to enter the thread kernel,
find there is a dead thread and try to free memory, therefore trying
to lock the malloc spinlock against itself.

The garbage collector thread acts just like any other thread, so
instead of having a spinlock to control accesses to the dead thread
list, it uses a mutex and a condition variable so that it can happily
wait to be signalled when a thread exists.

are started instead of init (pid = 1). This allows an embedded
implementation quite like VxWorks, with (possibly) a single threaded
program running instead of init. The neat thing is that the same threaded
process can run in a multi-user workstation environment too.

for the process, not a separate set for each thread). By default, the
process now only has signal handlers installed for SIGVTALRM, SIGINFO
and SIGCHLD. The thread kernel signal handler is installed for other
signals on demand. This means that SIG_IGN and SIG_DFL processing is now
left to the kernel, not the thread kernel.

Change the signal dispatch to no longer use a signal thread, and
call the signal handler using the stack of the thread that has the
signal pending.

Change the atomic lock method to use test-and-set asm code with
a yield if blocked. This introduces separate locks for each type
of object instead of blocking signals to prevent a context
switch. It was this blocking of signals that caused the performance
degradation the people have noted.

This is a *big* change!

specifically:
uthread_accept.c: Fix for inherited socket not getting correct entry in
                  pthread flags.
uthread_create.c: Fix to allow pthread_t pointer return to be null if
                  caller doesn't care about return.
uthread_fd.c: Fix for return codes to be placed into correct errno.
uthread_init.c: Changes to make gcc-2.8 thread aware for exception stack
                frames (WARNING: This is #ifdef'ed out by default and is
		different from the Cygnus egcs fix).
uthread_ioctl.c: Fix for blocking/non-blocking ioctl.
uthread_kern.c: Signal handling fixes (only one case left to fix,
                that of an externally sent SIGSEGV and friends -
		a fairly unusual case).
uthread_write.c: Fix for lock of fd - ask for write lock, not read/write.
uthread_writev.c: Fix for lock of fd - ask for write lock, not read/write.

Pthreads now works well enough to run the LDAP and ACAPD(with the gcc 2.8 fix)
sample implementations.