Issue #5249: time.strftime returned malformed string when format string
contained non ascii character on windows.
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index c32b53d..7e18086 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -508,9 +508,11 @@
             return NULL;
         }
 
-    /* Convert the unicode string to an ascii one */
-    fmt = _PyUnicode_AsString(format);
-
+	/* Convert the unicode string to an ascii one */
+	format = PyUnicode_AsEncodedString(format, TZNAME_ENCODING, NULL);
+	if (format == NULL)
+		return NULL;
+	fmt = PyBytes_AS_STRING(format);
 	fmtlen = strlen(fmt);
 
 	/* I hate these functions that presume you know how big the output
@@ -519,6 +521,7 @@
 	for (i = 1024; ; i += i) {
 		outbuf = (char *)PyMem_Malloc(i);
 		if (outbuf == NULL) {
+			Py_DECREF(format);
 			return PyErr_NoMemory();
 		}
 		buflen = strftime(outbuf, i, fmt, &buf);
@@ -532,6 +535,7 @@
 			ret = PyUnicode_Decode(outbuf, buflen,
 					       TZNAME_ENCODING, NULL);
 			PyMem_Free(outbuf);
+			Py_DECREF(format);
 			return ret;
 		}
 		PyMem_Free(outbuf);
@@ -539,6 +543,7 @@
 		/* VisualStudio .NET 2005 does this properly */
 		if (buflen == 0 && errno == EINVAL) {
 			PyErr_SetString(PyExc_ValueError, "Invalid format string");
+			Py_DECREF(format);
 			return 0;
 		}
 #endif