Sync with gcc:

Sync with gcc:
	* Makefile.def (target_modules): Add libgcc.
	(lang_env_dependencies): Remove default items.  Use no_c and no_gcc.
	* Makefile.tpl (clean-target-libgcc): Delete.
	(configure-target-[+module+]): Emit --disable-bootstrap dependencies
	on gcc even for bootstrapped modules.  Rewrite handling of
	lang_env_dependencies to loop over target_modules.
	* configure.in (target_libraries): Add target-libgcc.
	* Makefile.in, configure: Regenerated.