diff --git a/Modules/stropmodule.c b/Modules/stropmodule.c
index 2950b15..f37f000 100644
--- a/Modules/stropmodule.c
+++ b/Modules/stropmodule.c
@@ -878,7 +878,7 @@
 	PyObject *self; /* Not used */
 	PyObject *args;
 {
-	extern double strtod Py_PROTO((const char *, char **));
+	extern double strtod(const char *, char **);
 	char *s, *end;
 	double x;
 	char buffer[256]; /* For errors */