message: [Refactoring] Removed using namespace <xxx> from bench/ sources
  from bitcoin@73f41190b91dce9c125b1828b18f7625e0200145
diff: #include <iostream>
  #include <sys/time.h>
  -using namespace benchmark;
  -
  -std::map<std::string, BenchFunction> BenchRunner::benchmarks;
  +std::map<std::string, benchmark::BenchFunction> benchmark::BenchRunner::benchmarks;
  static double gettimedouble(void) {
  struct timeval tv;
  @@ -20,13 +18,13 @@ static double gettimedouble(void) {
  return tv.tv_usec * 0.000001 + tv.tv_sec;
  }
  -BenchRunner::BenchRunner(std::string name, BenchFunction func)
  +benchmark::BenchRunner::BenchRunner(std::string name, benchmark::BenchFunction func)
  {
  benchmarks.insert(std::make_pair(name, func));
  }
  void
  -BenchRunner::RunAll(double elapsedTimeForOne)
  +benchmark::BenchRunner::RunAll(double elapsedTimeForOne)
  {
  perf_init();
  std::cout << "#Benchmark" << "," << "count" << "," << "min" << "," << "max" << "," << "average" << ","
  @@ -42,7 +40,7 @@ BenchRunner::RunAll(double elapsedTimeForOne)
  perf_fini();
  }
  -bool State::KeepRunning()
  +bool benchmark::State::KeepRunning()
  {
  if (count & countMask) {
  ++count;
  