POSIX: Make sem_t self-contained

[Sebastian Huber]

Change the POSIX semaphore into a self-contained object using <sys/lock.h>, e.g.

typedef struct {
  struct _Semaphore_Control _sem;
} sem_t;

[Sebastian Huber <sebastian.huber@…>]

In 76d9db3/rtems-source-builder:

4.12: Update to Newlib 2.5.0.20170922

The time_t is now a 64-bit signed integer.

This update includes a patch to introduce the self-contained POSIX
synchronization objects.

Update #2514.
Update #3111.
Update #3112.
Update #3113.
Update #3114.
Update #3115.
Update #3116.

[Sebastian Huber <sebastian.huber@…>]

In e46a075/rtems:

Enforce compatible Newlib version

This Newlib check ensures that we have a 64-bit time_t and
self-contained POSIX synchronization objects.

Update #2514.
Update #3111.
Update #3112.
Update #3113.
Update #3114.
Update #3115.
Update #3116.

[Sebastian Huber <sebastian.huber@…>]

In c090db7/rtems:

posix: Implement self-contained POSIX semaphores

For semaphore object pointer and object validation see
POSIX_SEMAPHORE_VALIDATE_OBJECT().

Destruction or close of a busy semaphore returns an error status. The
object is not flushed.

POSIX semaphores are now available in all configurations and no longer
depend on --enable-posix.

Update #2514.
Update #3116.

[Sebastian Huber <sebastian.huber@…>]

In d8f7bdc/rtems-docs:

c-user: Add obsolete configuration options section

Update #2493.
Update #3112.
Update #3113.
Update #3114.
Update #3115.
Update #3116.

[Sebastian Huber <sebastian.huber@…>]

In 64564df/rtems-docs:

c-user: CONFIGURE_MAXIMUM_POSIX_SEMAPHORES

This configuration is not obsolete since it is still used for named
semaphores.

Update #3116.

[Sebastian Huber <sebastian.huber@…>]

In 9c0cefb/rtems:

confdefs: Add warnings for obsolete options

Update #2674.
Close #3112.
Close #3113.
Close #3114.
Close #3115.
Close #3116.

[Sebastian Huber]

Milestone renamed