Fix more gflag namespace issues

table/table_reader_bench.cc

@@ -3,6 +3,14 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
 
+#ifndef GFLAGS
+#include <cstdio>
+int main() {
+  fprintf(stderr, "Please install gflags to run rocksdb tools\n");
+  return 1;
+}
+#else
+
 #include <gflags/gflags.h>
 
 #include "rocksdb/db.h"
@@ -18,6 +26,9 @@
 #include "util/testharness.h"
 #include "util/testutil.h"
 
+using GFLAGS::ParseCommandLineFlags;
+using GFLAGS::SetUsageMessage;
+
 namespace rocksdb {
 
 namespace {
@@ -232,9 +243,9 @@ DEFINE_string(time_unit, "microsecond",
               "`microsecond` (default) or `nanosecond`");
 
 int main(int argc, char** argv) {
-  google::SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
-                          " [OPTIONS]...");
-  google::ParseCommandLineFlags(&argc, &argv, true);
+  SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
+                  " [OPTIONS]...");
+  ParseCommandLineFlags(&argc, &argv, true);
 
   rocksdb::TableFactory* tf = new rocksdb::BlockBasedTableFactory();
   rocksdb::Options options;
@@ -269,3 +280,5 @@ int main(int argc, char** argv) {
   delete tf;
   return 0;
 }
+
+#endif  // GFLAGS