pr27270 and pr27284, ar segfaults and wrong file mode

pr27270 and pr27284, ar segfaults and wrong file mode

	PR 27270
	PR 27284
	PR 26945
	* ar.c: Don't include libbfd.h.
	(write_archive): Replace xmalloc+strcpy with xstrdup.  Use
	bfd_stat rather than fstat on iostream.  Move stat and fd tests
	outside of _WIN32 ifdef.  Delete skip_stat variable.
	* arsup.c (temp_name, real_ofd): New static variables.
	(ar_open): Use make_tempname and bfd_fdopenw.
	(ar_save): Adjust to suit ar_open changes.  Move stat output
	of _WIN32 ifdef.
	* objcopy.c: Don't include libbfd.h.
	(copy_file): Use bfd_stat.