PR binutils/15140

	PR binutils/15140
	* ar.c (open_inarch): Fail on attempts to convert a normal archive
	to a thin archive or vice versa.
	* elfcomm.c (make_qualified_name): Handle corrupted thin
	archives.
	* readelf.c (process_archive): Likewise.
	* doc/binutils.texi: Clarify documentation describing thin
	archives.

	* archive.c (_bfd_get_elt_at_filepos): Prevent an infinite loop
	accessing a corrupt nested archive.