Added PyMac_BuildOptStr255, which returns None on a null pointer.

Mac/Include/macglue.h

@@ -105,6 +105,7 @@ PyObject *PyMac_BuildNumVersion(NumVersion);	/* Convert NumVersion to PyObject *
 
 int PyMac_GetStr255(PyObject *, Str255);	/* argument parser for Str255 */
 PyObject *PyMac_BuildStr255(Str255);		/* Convert Str255 to PyObject */
+PyObject *PyMac_BuildOptStr255(Str255);		/* Convert Str255 to PyObject, NULL to None */
 
 int PyMac_GetFSSpec(PyObject *, FSSpec *);	/* argument parser for FSSpec */
 PyObject *PyMac_BuildFSSpec(FSSpec *);		/* Convert FSSpec to PyObject */

Mac/Python/macglue.c

@@ -826,6 +826,20 @@ PyMac_GetStr255(PyObject *v, Str255 pbuf)
 PyObject *
 PyMac_BuildStr255(Str255 s)
 {
+	if ( s == NULL ) {
+		PyErr_SetString(PyExc_SystemError, "Str255 pointer is NULL");
+		return NULL;
+	}
+	return PyString_FromStringAndSize((char *)&s[1], (int)s[0]);
+}
+
+PyObject *
+PyMac_BuildOptStr255(Str255 s)
+{
+	if ( s == NULL ) {
+		Py_INCREF(Py_None);
+		return Py_None;
+	}
 	return PyString_FromStringAndSize((char *)&s[1], (int)s[0]);
 }