* configure.ac: Add GAS check for LEON instructions on SPARC.
	* configure: Regenerate.
	* config.in: Likewise.
	* config.gcc (with_cpu): Remove sparc-leon*-* and deal with LEON in the
	sparc*-*-* block.
	* config/sparc/sparc.opt (LEON, LEON3): New masks.
	* config/sparc/sparc.h (ASM_CPU32_DEFAULT_SPEC): Set to AS_LEON_FLAG
	for LEON or LEON3.
	(ASM_CPU_SPEC): Pass AS_LEON_FLAG if -mcpu=leon or -mcpu=leon3.
	(AS_LEON_FLAG): New macro.
	* config/sparc/sparc.c (sparc_option_override): Set MASK_LEON for leon
	and MASK_LEON3 for leon3 and unset them if HAVE_AS_LEON is not defined.
	Deal with LEON and LEON3 for the memory model.
	* config/sparc/sync.m (atomic_compare_and_swap<mode>): Enable for LEON3
	(atomic_compare_and_swap<mode>_1): Likewise.
	(*atomic_compare_and_swap<mode>_1): Likewise.

From-SVN: r201622