Trying again to fix error caused by -Wunused-function.

This thing with the pragma ignore was getting out of hand: now
MinGW (and probably GCC) was erroring too. So I chose to move
the definition of IsZero() out of the anonymous namespace into
benchmark.cc.

src/benchmark.cc

@@ -543,6 +543,10 @@ std::unique_ptr<BenchmarkReporter> CreateReporter(
 
 }  // end namespace
 
+bool IsZero(double n) {
+  return std::abs(n) < std::numeric_limits<double>::epsilon();
+}
+
 ConsoleReporter::OutputOptions GetOutputOptions(bool force_no_color) {
   int output_opts = ConsoleReporter::OO_Defaults;
   if ((FLAGS_benchmark_color == "auto" && IsColorTerminal()) ||

src/benchmark_api_internal.h

@@ -36,15 +36,10 @@ bool FindBenchmarksInternal(const std::string& re,
                             std::vector<Benchmark::Instance>* benchmarks,
                             std::ostream* Err);
 
+bool IsZero(double n);
+
 ConsoleReporter::OutputOptions GetOutputOptions(bool force_no_color = false);
 
-namespace {
-
-bool IsZero(double n) {
-  return std::abs(n) < std::numeric_limits<double>::epsilon();
-}
-
-}  // end namespace
 }  // end namespace internal
 }  // end namespace benchmark
 

test/output_test_helper.cc

@@ -7,16 +7,7 @@
 #include "../src/check.h"  // NOTE: check.h is for internal use only!
 #include "../src/re.h"     // NOTE: re.h is for internal use only
 #include "output_test.h"
-
-// clang fails with -Werror because IsZero() is not used in this library
-#ifdef __clang__
-# pragma clang diagnostic push
-# pragma clang diagnostic ignored "-Wunused-function"
-#endif
-#include "../src/benchmark_api_internal.h" // IsZero() is provided here
-#ifdef __clang__
-# pragma clang diagnostic pop
-#endif
+#include "../src/benchmark_api_internal.h"
 
 // ========================================================================= //
 // ------------------------------ Internals -------------------------------- //