* Makefile.am: split up BFD_LIBS like statements in BFD32_LIBS and

	* Makefile.am: split up BFD_LIBS like statements in BFD32_LIBS and
	BFD64_LIBS, make the latter depending on the availability of BFD64.
	Add archive64.c source file.
	* archive64.c: New file implementing bfd_elf64_archive_slurp_armap
	and bfd_elf64_archive_write_armap, code from elf64-mips.c
	* archive.c (bfd_slurp_armap): Add ELF64 archive support.
	* config.bfd (mips*-*-irix6*): Allow with BFD64 only.
	(mips64*el-*-linux*): Likewise.
	(mips*el-*-linux*): Likewise. Reorder entries.
	* configure.in (bfd_libs): Define in dependency of BFD64 and
	AC_SUBST it.
	* elf64-mips.c (mips_elf64_slurp_armap): Remove, use
	bfd_elf64_archive_slurp_armap instead.
	(mips_elf64_write_armap): Remove, use bfd_elf64_archive_write_armap
	instead.