INVALID_ERROR_CODE  937 contrib/tools/pngfix.c       case INVALID_ERROR_CODE:    return "invalid";
INVALID_ERROR_CODE  959 contrib/tools/pngfix.c       case INVALID_ERROR_CODE:    reason = "invalid"; break;
INVALID_ERROR_CODE 1184 contrib/tools/pngfix.c    stop(file, INVALID_ERROR_CODE, what);
INVALID_ERROR_CODE 1741 contrib/tools/pngfix.c    log_error(file, INVALID_ERROR_CODE, "iTXt chunk length");