Fix warnings.

stepmania/src/ScreenOptionsMaster.cpp

@@ -594,7 +594,7 @@ void ScreenOptionsMaster::RefreshIcons()
 			if( iSelection >= (int)m_OptionRow[i].choices.size() )
 			{
 				/* Invalid selection.  Send debug output, to aid debugging. */
-				CString error = ssprintf("Option row with name '%s' selects item %i, but there are only %i items:\n",
+				CString error = ssprintf("Option row with name '%s' selects item %i, but there are only %lu items:\n",
 					m_OptionRow[i].name.c_str(),
 					iSelection, m_OptionRow[i].choices.size() );