posix checklists

Missing routines for POSIX:

200112

• sem_timedwait: Disabled in libthread for some reason[optional]

• we only support the PTHREAD_PROCESS_PRIVATE as process-shared attribute for pthread_barrierattr*()[e.g. in pthread_barrierattr_setpshared()]

200809

• sigqueue : optional in 200112, required in 200809. We don't support sigqueue or any posix signal queuing.

• mq_notify doesn't support SIGEV_THREADThis would be fairly straightforward to support

• aio_notify doesn't support SIGEV_SIGNALThis is blocked by lack of proper SIGINFO

• POSIX aio is implemented by wrapping synchronous routines

• POSIX aio routines do not perform full set of required tests.

• open_memstream seek behaviour is not posix-compliant.

• O_CLOEXEC support