gcc/c/ChangeLog:

	PR middle-end/93926
	* c-decl.c (types_close_enough_to_match): New function.
	(match_builtin_function_types):
	(diagnose_mismatched_decls): Add missing inform call to a warning.

gcc/testsuite/ChangeLog:

	PR middle-end/93926
	* gcc.dg/Wbuiltin-declaration-mismatch-13.c: New test.