* ordered.c (gomp_ordered_sync): Add MEMMODEL_ACQ_REL fence.
	* critical.c (GOMP_critical_start): Add MEMMODEL_RELEASE fence.
	* config/linux/mutex.h: Use atomic rather than sync builtins.
	* config/linux/mutex.c: Likewise.  Comment.  Use -1 for waiting state.
	* config/linux/omp-lock.h: Comment fix.
	* config/linux/arm/mutex.h: Delete.
	* config/linux/powerpc/mutex.h: Delete.
	* config/linux/ia64/mutex.h: Delete.
	* config/linux/mips/mutex.h: Delete.

From-SVN: r181832