print build version when no input argument or with -v

@@ -1349,12 +1349,13 @@ int SrsConfig::parse_options(int argc, char** argv)
     }
     
     if (show_help) {
+        fprintf(stderr, "%s\n", VERSION_STRING);
         print_help(argv);
         exit(0);
     }
     
     if (show_version) {
-        fprintf(stderr, "%s\n", RTMP_SIG_SRS_VERSION);
+        fprintf(stderr, "%s\n%s\n", RTMP_SIG_SRS_VERSION, VERSION_STRING);
         exit(0);
     }