archive.c bfd_zalloc

archive.c bfd_zalloc

Quite a few bfd_zalloc calls are wasting time clearing memory, and
should be bfd_alloc instead.

	* archive.c (do_slurp_bsd_armap): Use bfd_alloc rather than
	bfd_zalloc when memory is all written after the call.
	(do_slurp_coff_armap): Likewise.  Set bfd_error on ridiculously
	large allocations that overflow bfd_size_type.  Use just one
	bfd_release on error exit.
	(_bfd_slurp_extended_name_table): Use bfd_alloc for extended_names,
	clear last byte rather than the entire array.  Use bfd_alloc for
	string table.  Rearrange and simplify code copying file names.