Minimal code changes to allow msvc compilation.

src/bench/base58.cpp

@@ -22,7 +22,7 @@ static void Base58Encode(benchmark::State& state)
         }
     };
     while (state.KeepRunning()) {
-        EncodeBase58(buff.begin(), buff.end());
+        EncodeBase58(buff.data(), buff.data() + buff.size());
     }
 }
 

src/bench/checkqueue.cpp

@@ -19,7 +19,7 @@ static const int MIN_CORES = 2;
 static const size_t BATCHES = 101;
 static const size_t BATCH_SIZE = 30;
 static const int PREVECTOR_SIZE = 28;
-static const int QUEUE_BATCH_SIZE = 128;
+static const unsigned int QUEUE_BATCH_SIZE = 128;
 static void CCheckQueueSpeed(benchmark::State& state)
 {
     struct FakeJobNoWork {