Add an option to the archiver to add a section recording library dependencies.

Add an option to the archiver to add a section recording library dependencies.

	* ar.c (long_options): Add --record-libdeps.
	(usage): Mention the new option.
	(decode_options): Handle the new option.
	(replace_members): If necessary, create a bfd to hold the libdeps
	description.
	* binemul.c (ar_emul_append_bfd): New function.
	(ar_emul_replace_bfd): New function.
	(ar_emul_default_append): Replace file_name and target arguments
	with new_bfd argument.
	(ar_emul_default_replace): Likewise.
	* binemul.h: Update prototypes.
	(struct bin_emulation_xfer_struct): Update fields.
	* doc/binutils.texi: Document the new option.
	* NEWS: Mention the new feature.
	* emul_aix.c (ar_emul_aix_append): Update.
	(ar_emul_aix_replace): Likewise.
	* testsuite/binutils-all/ar.exp: Add test of new feature.