Issue #6368: Fixed unused variable warning on Unix.
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index 4c523d4..3220702 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -2238,7 +2238,9 @@
 	char *mode = "r";
 	int bufsize = -1;
 	int wideargument = 0;
+#ifdef MS_WINDOWS
 	PyObject *po;
+#endif
 
 	assert(PyFile_Check(self));
 	if (foself->f_fp != NULL) {