pthread-thread: New module.

pthread-thread: New module.

* lib/pthread.in.h (pthread_create, pthread_exit, pthread_join): Remove
inline definitions.
* lib/pthread-thread.c: New file.
* m4/pthread-thread.m4: New file.
* modules/pthread-thread: New file.
* doc/posix-functions/pthread_create.texi: Mention the new module.
* doc/posix-functions/pthread_attr_init.texi: Likewise.
* doc/posix-functions/pthread_attr_getdetachstate.texi: Likewise.
* doc/posix-functions/pthread_attr_setdetachstate.texi: Likewise.
* doc/posix-functions/pthread_attr_destroy.texi: Likewise.
* doc/posix-functions/pthread_self.texi: Likewise.
* doc/posix-functions/pthread_equal.texi: Likewise.
* doc/posix-functions/pthread_detach.texi: Likewise.
* doc/posix-functions/pthread_join.texi: Likewise.
* doc/posix-functions/pthread_exit.texi: Likewise.