diff --git a/Python/errors.c b/Python/errors.c
index 526b61b..c7e9528 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -84,8 +84,10 @@
 #endif /* macintosh */
 
 #ifndef __STDC__
+#ifndef MS_WINDOWS
 extern char *strerror PROTO((int));
 #endif
+#endif
 
 /* Last exception stored by err_setval() */