folly: fix clang build with -Wunused-const-variable

Summary: Fix a few unused const variables exposed by clang's `-Wunused-const-variable`.

Reviewed By: yfeldblum

Differential Revision: D2878944

fb-gh-sync-id: f5500fda4782eac2964761c0398d016d57716269

folly/experimental/test/BitVectorCodingTest.cpp

@@ -70,8 +70,6 @@ TEST_F(BitVectorCodingTest, SkipForwardPointers) {
 
 namespace bm {
 
-constexpr size_t k1M = 1000000;
-
 typedef BitVectorEncoder<uint32_t, uint32_t, 128, 128> Encoder;
 typedef BitVectorReader<Encoder> Reader;
 

folly/experimental/test/EliasFanoCodingTest.cpp

@@ -84,8 +84,6 @@ TEST_F(EliasFanoCodingTest, Select64) {
 
 namespace bm {
 
-constexpr size_t k1M = 1000000;
-
 typedef EliasFanoEncoderV2<uint32_t, uint32_t, 128, 128> Encoder;
 typedef EliasFanoReader<Encoder> Reader;
 

folly/io/async/EventBase.cpp

@@ -55,8 +55,6 @@ class FunctionLoopCallback : public EventBase::LoopCallback {
 
 namespace folly {
 
-const int kNoFD = -1;
-
 /*
  * EventBase::FunctionRunner
  */

folly/test/FBStringBenchmark.cpp

@@ -39,8 +39,6 @@ using namespace folly;
 static const int seed = folly::randomNumberSeed();
 typedef boost::mt19937 RandomT;
 static RandomT rng(seed);
-static const size_t maxString = 100;
-static const bool avoidAliasing = true;
 
 template <class Integral1, class Integral2>
 Integral2 random(Integral1 low, Integral2 up) {

folly/test/FBVectorBenchmark.cpp

@@ -37,8 +37,6 @@ using namespace folly;
 auto static const seed = randomNumberSeed();
 typedef boost::mt19937 RandomT;
 static RandomT rng(seed);
-static const size_t maxString = 100;
-static const bool avoidAliasing = true;
 
 template <class Integral1, class Integral2>
 Integral2 random(Integral1 low, Integral2 up) {

folly/test/FBVectorTest.cpp

@@ -37,8 +37,6 @@ using namespace folly;
 auto static const seed = randomNumberSeed();
 typedef boost::mt19937 RandomT;
 static RandomT rng(seed);
-static const size_t maxString = 100;
-static const bool avoidAliasing = true;
 
 template <class Integral1, class Integral2>
 Integral2 random(Integral1 low, Integral2 up) {