bfd/ChangeLog

	* elf32-avr.c: Add DIFF relocations for AVR.
	(avr_final_link_relocate): Handle the DIFF relocs.
	(bfd_elf_avr_diff_reloc): New.
	(elf32_avr_is_diff_reloc): New.
	(elf32_avr_adjust_diff_reloc_value): Reduce difference value.
	(elf32_avr_relax_delete_bytes): Recompute difference after deleting
	bytes.

	* reloc.c: Add BFD_RELOC_AVR_DIFF8/16/32 relocations

gas/ChangeLog

	* config/tc-avr.c: Add new flag mlink-relax.
	(md_show_usage): Add flag and help text.
	(md_parse_option): Record whether link relax is turned on.
	(relaxable_section): New.
	(avr_validate_fix_sub): New.
	(avr_force_relocation): New.
	(md_apply_fix): Generate DIFF reloc.
	(avr_allow_local_subtract): New.

	* config/tc-avr.h (TC_LINKRELAX_FIXUP): Define to 0.
	(TC_FORCE_RELOCATION): Define.
	(TC_FORCE_RELOCATION_SUB_SAME): Define.
	(TC_VALIDATE_FIX_SUB): Define.
	(avr_force_relocation): Declare.
	(avr_validate_fix_sub): Declare.
	(md_allow_local_subtract): Define.
	(avr_allow_local_subtract): Declare.

gas/testsuite/ChangeLog

	* gas/avr/diffreloc_withrelax.d: New testcase.
	* gas/avr/noreloc_withoutrelax.d: Likewise.
	* gas/avr/relax.s: Likewise.

include/ChangeLog

	* elf/avr.h: Add new DIFF relocs.

ld/testsuite/ChangeLog

	* ld-avr/norelax_diff.d: New testcase.
	* ld-avr/relax_diff.d: Likewise.
	* ld-avr/relax.s: Likewise.