BFD_RELOC_MIPS_16

BFD_RELOC_MIPS_16

MIPS should not be using BFD_RELOC_16 for its R_MIPS_16 relocation,
since R_MIPS_16 specifies a 16-bit field in a 32-bit word.
BFD_RELOC_16, emitted by generic code to handle fixups on 16-bit data
directives, expects fixups to operate on the whole of a 16-bit word.

This patch corrects the problem by using BFD_RELOC_MIPS_16, a new bfd
reloc that is used to generate R_MIPS_16.  BFD_RELOC_16 is handled in
md_apply_fix for cases where the fixup can be applied at assembly
time.  Like BFD_RELOC_8, BFD_RELOC_16 now has no corresponding object
file relocation, and thus .half, .hword, .short and .dc.w must be
resolved at assembly time.  BFD_RELOC_MIPS_REL16 is removed by this
patch since it isn't used.

	PR 3243
	PR 26542
	* reloc.c (BFD_RELOC_MIPS_16): Rename from BFD_RELOC_MIPS_REL16.
	* elf32-mips.c (mips_reloc_map): Map BFD_RELOC_MIPS_16 to R_MIPS_16.
	* elf64-mips.c (mips_reloc_map): Likewise, delete BFD_RELOC_MIPS_REL16.
	* elfn32-mips.c (mips_reloc_map): Likewise.
	* libbfd.h: Regenerate.
	* bfd-in2.h: Regenerate.
gas/
	* config/tc-mips.c (append_insn): Handle BFD_RELOC_MIPS_16.
	(macro_build): Likewise.
	(mips_percent_op <%half>): Generate BFD_RELOC_MIPS_16.
	(md_apply_fix): Handle BFD_RELOC_16 and BFD_RELOC_MIPS_16 when fx_done.
ld/
	* testsuite/ld-mips-elf/reloc-local-overflow.d,
	* testsuite/ld-mips-elf/reloc-local-overflow.s: Rewrite.