Fix a conflict between the linker's need to rename some PE format input libraries...

Fix a conflict between the linker's need to rename some PE format input libraries and the BFD library's file caching mechanism.

	PR 29389
bfd	* bfd.c (BFD_CLOSED_BY_CACHE): New bfd flag.
	* cache.c (bfd_cache_delete): Set BFD_CLOSED_BY_DELETE on the
	closed bfd.
	(bfd_cache_lookup_worker): Clear BFD_CLOSED_BY_DELETE on the newly
	reopened bfd.
	* opncls.c (bfd_set_filename): Refuse to change the name of a bfd
	that has been closed by bfd_cache_delete.  Mark changed bfds as
	uncacheable.
	* bfd-in2.h: Regenerate.

ld	* ldlang.h (lang_input_statement_struct): Add sort_key field.
	* emultempl/pe.em (after_open): If multiple import libraries refer
	to the same bfd, store their names in the sort_key field.
	* emultempl/pep.em (after_open): Likewise.
	* ldlang.c (sort_filename): New function.  Returns the filename to
	be used when sorting input files.
	(wild_sort): Use the sort_filename function.