configure.ac (--enable-lto): Add x86_64-apple-darwin* as a platform that supports LTO.

ChangeLog:
	* configure.ac (--enable-lto): Add x86_64-apple-darwin* as
	a platform that supports LTO.
	* configure: Regenerate.

gcc/ChangeLog:
	* config.gcc (i[34567]86-*-darwin*, x86_64-*-darwin*): Add
	lto-macho as lto_binary_reader.
	* target.h (struct gcc_target): New hooks lto_start and	lto_end.
	* target-def.h (TARGET_ASM_LTO_START, TARGET_ASM_LTO_END): Define.
	* cgraphunit.c (ipa_passes): Wrap LTO assembler output generation
	in lto_start and lto_end calls.
	(is_elf_or_coff): Rename to maybe_lto_object_file.  Add Mach-O
	magic numbers.
	(scan_prog_file): Update is_elf_or_coff call.
	* doc/tm.text (TARGET_ASM_LTO_START, TARGET_ASM_LTO_END): Document.

	* collect2.c (main): Fix enum comparison.

	* config/darwin-protos.h (darwin_asm_lto_start, darwin_asm_lto_end):
	Add prototypes.
	* darwin9.h (LINK_COMMAND_SPEC): Pass -flto and -fwhopr to the linker.
	* darwin.h (LINK_COMMAND_SPEC): Likewise.  Define TARGET_ASM_LTO_START
	and TARGET_ASM_LTO_END.
	* darwin.c: Include obstack.h and lto-streamer.h.
	(lto_section_names_offset, lto_section_names_obstack,
	lto_asm_out_file, lto_asm_out_name, saved_asm_out_file): New static
	global variables.
	(LTO_SEGMENT_NAME, LTO_NAMES_SECTION): New defines.
	(darwin_asm_lto_start): New function.  Redirect output to asm_out_file
	to a temporary file.
	(darwin_asm_lto_end): New function.  Restore asm_out_file.
	(darwin_asm_named_section): For LTO sections, replace the name with
	the offset of the section name in a string table, and build this
	table.
	(darwin_file_start): Initialize global vars for LTO support.
	(darwin_file_end): If output to asm_out_file was redirected, append it
	to the proper asm_out_file here.  Add the section names section.

lto/ChangeLog:
	* lto.h (struct lto_file_struct): Document offset member.
	* lto-endian.h: New file.
	* lto-macho.h: New file.
	* lto-macho.c: New file.
	* Make-lang.in: Add rule for lto-macho.o.

From-SVN: r159173