cpplib.h (struct cpp_callbacks): Add user_builtin_macro callback.

cpplib.h (struct cpp_callbacks): Add user_builtin_macro callback.

	* include/cpplib.h (struct cpp_callbacks): Add user_builtin_macro
	callback.
	(enum cpp_builtin_type): Add BT_FIRST_USER and BT_LAST_USER.
	(cpp_macro_definition): Remove const qual from second argument.
	* macro.c (enter_macro_context): Call user_builtin_macro callback for
	NODE_BUILTIN !NODE_USED macros.
	(warn_of_redefinition): Likewise.  Remove const qual from second
	argument.
	(cpp_macro_definition): Likewise.
	* pch.c (write_macdef, save_macros): Call user_builtin_macro callback
	for NODE_BUILTIN !NODE_USED macros.

	* c-family/c-cppbuiltin.c: Include cpp-id-data.h.
	(lazy_hex_fp_values, lazy_hex_fp_value_count): New variables.
	(lazy_hex_fp_value): New function.
	(builtin_define_with_hex_fp_value): Provide definitions lazily.
	* Makefile.in (c-family/c-cppbuiltin.o): Depend on $(CPP_ID_DATA_H).

From-SVN: r160626