libbacktrace/:
	* macho.c (MACH_O_MH_MAGIC_FAT_64): Define.
	(MACH_O_MH_CIGAM_FAT_64): Define.
	(struct macho_fat_arch_64): Define.
	(macho_add_fat): Add and use is_64 parameter.
	(macho_add): Recognize 64-bit fat files.