lto: Don't include unused LTO archive members in output

When plugin_object_p is called by elf_link_is_defined_archive_symbol to
check if a symbol in archive is a real definition, set archive member
plugin_format to bfd_plugin_yes_unused to avoid including the unused LTO
archive members in linker output.  When plugin_object_p is called as
known used, call plugin claim_file if plugin_format is bfd_plugin_unknown
or bfd_plugin_yes_unused.

To get the proper support for archives with LTO common symbols with GCC,
the GCC fix for

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116361



is needed.

bfd/

	PR ld/32083
	* archures.c (bfd_arch_get_compatible): Treat bfd_plugin_yes_unused
	the same as bfd_plugin_yes.
	* elflink.c (elf_link_is_defined_archive_symbol): Likewise.
	* bfd.c (bfd_plugin_format): Add bfd_plugin_yes_unused.
	* plugin.c (try_claim): Try claim_file_v2 first.
	* bfd-in2.h: Regenerated.

ld/

	PR ld/32083
	* plugin.c (plugin_call_claim_file): Add an argument to return
	if LDPT_REGISTER_CLAIM_FILE_HOOK_V2 is used.
	(plugin_object_p): When KNOWN_USED is false, we call plugin
	claim_file if plugin_format is bfd_plugin_unknown and set
	plugin_format to bfd_plugin_yes_unused on LTO object.  When
	KNOWN_USED is true, we call plugin claim_file if plugin_format
	is bfd_plugin_unknown or bfd_plugin_yes_unused.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>