Limit BFD_SUPPORTS_PLUGINS check to plugin.h and targets.c

Limit BFD_SUPPORTS_PLUGINS check to plugin.h and targets.c

Minimize the BFD_SUPPORTS_PLUGINS check to make code more readable and
maintainable by:

1. Update bfd/plugin.h to define plugin functions as static inline if
BFD_SUPPORTS_PLUGINS is 0.
2. Remove BFD_SUPPORTS_PLUGINS check from all bfd and binutils files
except plugin.h and targets.c.
3. Replace the remaining BFD_SUPPORTS_PLUGINS checks with a function so
that plugin availability is checked at run time.

bfd/

	* archive.c: Include plugin.h unconditionally.
	(_bfd_compute_and_write_armap): Remove the BFD_SUPPORTS_PLUGINS
	check.
	* bfd-in.h (bfd_plugin_enabled): New.
	* bfd-in2.h: Regenerated.
	* elflink.c: Include plugin.h unconditionally.
	(elf_link_is_defined_archive_symbol): Remove the
	BFD_SUPPORTS_PLUGINS check.
	* format.c: Include plugin.h unconditionally.
	(bfd_set_lto_type): Remove the BFD_SUPPORTS_PLUGINS check.
	(bfd_check_format_matches): Replace the BFD_SUPPORTS_PLUGINS
	check with the bfd_plugin_enabled call.  Replace plugin_vec
	with bfd_plugin_vec.  Remove the BFD_SUPPORTS_PLUGINS check.
	* plugin.c (bfd_plugin_target_p): Removed.
	* plugin.h (bfd_plugin_vec): New.
	(bfd_plugin_target_p): Likewise.
	(bfd_plugin_set_program_name): New.  Static inline
	function if BFD_SUPPORTS_PLUGINS is 0.
	(bfd_plugin_open_input): Likewise.
	(bfd_plugin_set_plugin): Likewise.
	(bfd_link_plugin_object_p): Likewise.
	(register_ld_plugin_object_p): Likewise.
	(bfd_plugin_close_file_descriptor): Likewise.
	(bfd_plugin_vec): Likewise.
	(bfd_plugin_target_p): Likewise.
	* xtensa-dynconfig.c (xtensa_load_config): Replace the
	BFD_SUPPORTS_PLUGINS check with the bfd_plugin_enabled call.

ar/

	* ar.c: Include plugin.h unconditionally.
	(plugin_target): Removed.
	(usage): Replace the BFD_SUPPORTS_PLUGINS check with the
	bfd_plugin_enabled call.
	(ranlib_usage): Likewise.
	(decode_options): Likewise.
	(ranlib_main): Likewise.
	(main): Call bfd_plugin_set_program_name unconditionally.
	* nm.c: Include plugin.h unconditionally.
	(plugin_target): Removed.
	(usage): Replace the BFD_SUPPORTS_PLUGINS check with the
	bfd_plugin_enabled call.
	(filter_symbols): Remove the BFD_SUPPORTS_PLUGINS check.
	(display_rel_file): Likewise.
	(main): Call bfd_plugin_set_program_name unconditionally.  Replace
	the BFD_SUPPORTS_PLUGINS check with the bfd_plugin_enabled call.
	* objcopy.c: Include plugin.h unconditionally.
	(strip_usage): Replace the BFD_SUPPORTS_PLUGINS check with the
	bfd_plugin_enabled call.
	(copy_archive): Remove the BFD_SUPPORTS_PLUGINS check.  Replace
	BFD_SUPPORTS_PLUGINS with the bfd_plugin_enabled call.
	(copy_file): Likewise.
	(strip_main): Likewise.

ld/

	* ldfile.c: Include plugin.h unconditionally.
	(ldfile_try_open_bfd): Remove the BFD_SUPPORTS_PLUGINS check.
	* ldlang.c: Include plugin.h unconditionally.
	(plugin_insert): Remove the BFD_SUPPORTS_PLUGINS check.
	(plugin_undefs): Likewise.
	(open_input_bfds): Likewise.
	(lang_check): Likewise.
	(lang_gc_sections): Likewise.
	(find_next_input_statement): Likewise.
	(lang_process): Likewise.
	* ldlang.h (lang_input_statement_flags): Likewise.
	* ldlex.h (option_values): Likewise.
	* ldmain.c: Include plugin.h unconditionally.
	(ld_cleanup): Remove the BFD_SUPPORTS_PLUGINS check.
	(main): Likewise.
	(add_archive_element): Likewise.
	* lexsup.c: Include plugin.h unconditionally.
	(ld_options): Remove the BFD_SUPPORTS_PLUGINS check.
	(parse_args): Replace the BFD_SUPPORTS_PLUGINS check with the
	bfd_plugin_enabled call.  Remove the BFD_SUPPORTS_PLUGINS check.
	(help): Append " (ignored)" to plugin options if bfd_plugin_enabled
	return false.
	* libdep_plugin.c: Remove the BFD_SUPPORTS_PLUGINS check.
	* plugin.c: Likewise.
	* testplug.c: Likewise.
	* testplug2.c: Likewise.
	* testplug3.c: Likewise.
	* testplug4.c: Likewise.

Co-Authored-By: Alan Modra <amodra@gmail.com>
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>