* langhooks.c (lang_hook_default_do_nothing,
	lang_hook_default_decode_option): New defaults.
	* langhooks.h: Make hooks unconditional and non-NULL.
	* toplev.c (compile_file, toplev_main): Update.
	* toplev.h: Update comments.
	* objc/objc-act.c (lang_hooks): Update to new paradigm.

From-SVN: r46396