gas/

gas/
	* config/tc-mips.h (DIFF_EXPR_OK, CFI_DIFF_EXPR_OK): Define.
	* config/tc-mips.c (md_pcrel_from): Remove error message.
	(md_apply_fix): Convert PC-relative BFD_RELOC_32s to
	BFD_RELOC_32_PCREL.  Report a specific error message for unhandled
	PC-relative expressions.  Handle BFD_RELOC_8.

gas/testsuite/
	* gas/all/gas.exp: Remove XFAIL of forward.d for MIPS.
	* gas/mips/pcrel-1.s, gas/mips/pcrel-1.d, gas/mips/pcrel-2.s,
	gas/mips/pcrel-2.d, gas/mips/pcrel-3.s, gas/mips/pcrel-3.l,
	gas/mips/pcrel-4.s, gas/mips/pcrel-4-32.d, gas/mips/pcrel-4-n32.d,
	gas/mips/pcrel-4-64.d: New tests.
	* gas/mips/mips.exp: Run them.
	* gas/mips/lui-2.l: Tweak error message for line 7.

ld/testsuite/
	* ld-elf/merge.d: Remove MIPS XFAIL.