* langhooks.c (lang_hook_default_clear_binding_stack): New.
(lang_hook_default_get_alias_set): Move next to other alias
hooks.
* langhooks.h: Prototype lang_hook_default_clear_binding_stack.
(LANG_HOOKS_CLEAR_BINDING_STACK): New macro.
(LANG_HOOKS_INITIALIZER): Add it.
* toplev.h (struct lang_hooks): Add clear_binding_stack.
* toplev.c (compile_file): Call lang_hooks.clear_binding_stack
instead of a loop calling poplevel.
cp:
* cp-lang.c: Redefine LANG_HOOKS_CLEAR_BINDING_STACK to
pop_everything.