* Makefile.in (c-lex.o): Update.
	* c-lex.c: Include target.h.
	(cb_register_builtins): New.
	(init_c_lex): Set builtins callback.
	* c-lex.h (cpp_define, cpp_assert): New prototypes.
	* cppinit.c (init_builtins): Use callback, including for
	GXX_WEAK.
	* cpplib.h (struct cpp_callbacks): New member.
	* target-def.h (TARGET_REGISTER_CPP_BUILTINS): New.
	(TARGET_INITIALIZER): Update.
	* target.h (struct gcc_target): New hook.
	* tree.c (default_register_cpp_builtins): New.
	* tree.h (default_register_cpp_builtins): New.
doc:
	* tm.texi (TARGET_REGISTER_CPP_BUILTINS): Document.

From-SVN: r53165