acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t.

acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t.

2015-03-18  Jonathan Wakely  <jwakely@redhat.com>
	    Torvald Riegel  <triegel@redhat.com>

	* acinclude.m4 (GLIBCXX_CHECK_GTHREADS): Check for pthread_rwlock_t.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/std/shared_mutex: Check _GLIBCXX_USE_PTHREAD_RWLOCK_T.
	(shared_timed_mutex::_M_rwlock): Use PTHREAD_RWLOCK_INITIALIZER.
	(shared_timed_mutex::lock_shared()): Retry on EAGAIN.
	(shared_timed_mutex::try_lock_shared_until()): Retry on EAGAIN and
	EDEADLK.

Co-Authored-By: Torvald Riegel <triegel@redhat.com>
From-SVN: r221484