flush errorlog to stderr

src/stderr.c

@@ -31,6 +31,7 @@ void
 logStderr(void * this, TR_logger_level level, const char * const msg)
 {
 	fprintf(stderr, "[%s] %s\n", TR_logger_level_str[level], msg);
+	fflush(stderr);
 }
 
 TR_INIT_IFACE(TR_Logger, logStderr);