* configure.ac: Tweak GAS check for LEON instructions on SPARC.
	* configure: Regenerate.
	* config/sparc/sparc.opt (muser-mode): New option.
	* config/sparc/sync.md (atomic_compare_and_swap<mode>_1): Do not enable
	for LEON3.
	(atomic_compare_and_swap_leon3_1): New instruction for LEON3.
	* doc/invoke.texi (SPARC options): Document -muser-mode.

From-SVN: r209850