* config/tc-mips.h (DIFF_EXPR_OK): Define.

	* config/tc-mips.h (DIFF_EXPR_OK): Define.
	* config/tc-mips.c (macro_build): Permit BFD_RELOC_PCREL_LO16 for
	certain cases of 'i', 'j' and 'o'.  Change 'u' to take an
	argument, the reloc type.
	(load_register): Pass reloc type to macro_build for 'u'.
	(macro): Likewise.  For M_LA_AB permit a difference expression
	when generating embedded PIC code between an arbitrary symbol and
	a symbol in the .text section.
	(mips_force_relocation): Force BFD_RELOC_PCREL_HI16_S and
	BFD_RELOC_PCREL_LO16 to be emitted.
	(md_apply_fix): Check that most relocs are not PC relative.
	Handle BFD_RELOC_PCREL_HI16_S and BFD_RELOC_PCREL_LO16.
	(tc_gen_reloc): Change #error to as_fatal.  Handle
	BFD_RELOC_PCREL_LO16 and BFD_RELOC_PCREL_HI16_S.