PR c/94040 - ICE on a call to an invalid redeclaration of strftime

PR c/94040 - ICE on a call to an invalid redeclaration of strftime

gcc/c/ChangeLog:

	PR c/94040
	* c-decl.c (builtin_structptr_type_count): New constant.
	(match_builtin_function_types): Reject decls that are incompatible
	in types pointed to by pointers.
	(diagnose_mismatched_decls): Adjust comments.

gcc/testsuite/ChangeLog:

	PR c/94040
	* gcc.dg/Wbuiltin-declaration-mismatch-12.c: Relax test to look
	for warning name rather than the exact text.
	* gcc.dg/Wbuiltin-declaration-mismatch-14.c: New test.
	* gcc.dg/Wbuiltin-declaration-mismatch-15.c: New test.
	* gcc.dg/pr62090.c: Prune expected warning.
	* gcc.dg/pr89314.c: Look for warning name rather than text.