diff --git a/Python/pythonmain.c b/Python/pythonmain.c
index aee8664b306..6602e2b3d29 100644
--- a/Python/pythonmain.c
+++ b/Python/pythonmain.c
@@ -425,6 +425,16 @@ isatty(fd)
 	return fd == fileno(stdin);
 }
 
+#ifdef macintosh
+/* same */
+int
+isatty(fd)
+	int fd;
+{
+	return fd == fileno(stdin);
+}
+#endif
+
 #endif
 
 /*	XXX WISH LIST