configure.in: Check whether gas supports -relax.

configure.in: Check whether gas supports -relax.

	* configure.in: Check whether gas supports -relax.
	* configure, config.in: Rebuilt.
	* config/sparc/sparc.h (ASM_RELAX_SPEC): Define.
	(EXTRA_SPECS): Add asm_relax.
	(ASM_SPEC): Add %(asm_relax).
	(TARGET_SWITCHES): Add -mrelax and -mno-relax.
	* config/sparc/linux64.h (LINK_ARCH_SPEC): Rename to LINK_SPEC.
	(LINK_SPEC): Pass -relax to linker unless -mno-relax or -r.
	(ASM_SPEC): Add %(asm_relax).
	* config/sparc/linux.h (LINK_SPEC, ASM_SPEC): Likewise.
	* config/sparc/sparc.c (output_sibcall): If HAVE_AS_RELAX_OPTION,
	never use sethi/jmpl for leaf tail calls.  Use or with rs2 %g0
	instead of mov, so that gas can further optimize it.

From-SVN: r34466