* langhooks.h: New file.
* Makefile.in (OBJS): Added langhooks.o.
(c-lang.o): Depend on langhooks.h.
(c-common.o): Don't depend on tree-inline.h.
(tree-inline.o): Depend on toplev.h.
(langhooks.o): New rule.
* c-common.c: Don't include tree-inline.h.
(c_mark_lang_decl): Mark argument c as unused.
(c_common_lang_init): Don't initialize hooks here.
* c-lang.c: Include langhooks.h, then override some macros.
(lang_hooks): Initialize with macros in langhooks.h.
(c_init): Don't initialize hooks here.
* toplev.c (struct lang_hooks_for_tree_inlining): New struct.
(struct lang_hooks): Add tree_inlining.  Refer to langhooks.h.
* tree-inline.c: Include toplev.h.  Don't define hook variables.
* tree-inline.h: Don't define hook types nor declare hook
variables.  Move macros to...
* langhooks.c: ... new file, as functions.  Adjust all callers.

From-SVN: r46096