pthread_cond_timedwait(3): accept negative absolute timeouts

Negative absolute timeouts are valid inputs.

With input from kettenis@.

Thread: https://marc.info/?l=openbsd-tech&m=170467558006767&w=2

ok guenther@

Validate timespec and return ECANCELED when interrupted with SA_RESTART.

Discussing with mpi@ and guenther@, we decided to first fix the existing
semaphore implementation with regards to SA_RESTART and POSIX compliant
returns in the case where we deal with restartable signals.

Currently we return EINTR everywhere which is mostly incorrect as the
user can not know if she needs to recall the syscall or not. Return
ECANCELED to signal that SA_RESTART was set and EINTR otherwise.

Regression tests pass and so does the posixsuite. Timespec validation
bits are needed to pass the later.

OK mpi@, guenther@

Move mutex, condvar, and thread-specific data routes, pthread_once, and
pthread_exit from libpthread to libc, along with low-level bits to
support them. Major bump to both libc and libpthread.

Requested by libressl team. Ports testing by naddy@
ok kettenis@

s/DEF_STD/DEF_STRONG/ to match namespace.h differences between librthread
and libc

Sort headers per style(9)

Copy files from ../librthread in preparation for moving functionality
from libpthread to libc. No changes to the build yet, just making it
easier to review the substantive diffs.

ok beck@ kettenis@ tedu@

Validate timespec and return ECANCELED when interrupted with SA_RESTART.

Discussing with mpi@ and guenther@, we decided to first fix the existing
semaphore implementation with regards to SA_RESTART and POSIX compliant
returns in the case where we deal with restartable signals.

Currently we return EINTR everywhere which is mostly incorrect as the
user can not know if she needs to recall the syscall or not. Return
ECANCELED to signal that SA_RESTART was set and EINTR otherwise.

Regression tests pass and so does the posixsuite. Timespec validation
bits are needed to pass the later.

OK mpi@, guenther@

Move mutex, condvar, and thread-specific data routes, pthread_once, and
pthread_exit from libpthread to libc, along with low-level bits to
support them. Major bump to both libc and libpthread.

Requested by libressl team. Ports testing by naddy@
ok kettenis@

s/DEF_STD/DEF_STRONG/ to match namespace.h differences between librthread
and libc

Sort headers per style(9)

Copy files from ../librthread in preparation for moving functionality
from libpthread to libc. No changes to the build yet, just making it
easier to review the substantive diffs.

ok beck@ kettenis@ tedu@

Move mutex, condvar, and thread-specific data routes, pthread_once, and
pthread_exit from libpthread to libc, along with low-level bits to
support them. Major bump to both libc and libpthread.

Requested by libressl team. Ports testing by naddy@
ok kettenis@

s/DEF_STD/DEF_STRONG/ to match namespace.h differences between librthread
and libc

Sort headers per style(9)

Copy files from ../librthread in preparation for moving functionality
from libpthread to libc. No changes to the build yet, just making it
easier to review the substantive diffs.

ok beck@ kettenis@ tedu@