message: Use C++11 compatible version of static_assert; before
  C++17 the second message parameter to static_assert was
  not optional.
  Some particularly old compiler (gcc-5) was having trouble
diff: @@ -46,7 +46,8 @@ TEST(ForwardReferenceElseConstructTest, ForwardReferenceConst) {
  TEST(ForwardReferenceElseConstructTest, Construct) {
  const TestClassA a;
  const auto& ref = ForwardReferenceElseConstruct<TestClassB>()(a);
  - static_assert(!std::is_same<decltype(ref), TestClassA>::value);
  + static_assert(!std::is_same<decltype(ref), TestClassA>::value,
  + "!std::is_same<decltype(ref), TestClassA>::value");
  }
  TEST(ForwardReferenceElseConstructTest, ForwardStringView) {
  @@ -58,7 +59,8 @@ TEST(ForwardReferenceElseConstructTest, ForwardStringView) {
  TEST(ForwardReferenceElseConstructTest, ConstructString) {
  const absl::string_view a("hello");
  const auto& ref = ForwardReferenceElseConstruct<std::string>()(a);
  - static_assert(!std::is_same<decltype(ref), absl::string_view>::value);
  + static_assert(!std::is_same<decltype(ref), absl::string_view>::value,
  + "!std::is_same<decltype(ref), absl::string_view>::value");
  }
  TEST(ForwardReferenceElseConstructTest, ForwardString) {
  @@ -70,7 +72,8 @@ TEST(ForwardReferenceElseConstructTest, ForwardString) {
  TEST(ForwardReferenceElseConstructTest, ConstructStringView) {
  const std::string a("hello");
  const auto& ref = ForwardReferenceElseConstruct<absl::string_view>()(a);
  - static_assert(!std::is_same<decltype(ref), std::string>::value);
  + static_assert(!std::is_same<decltype(ref), std::string>::value,
  + "!std::is_same<decltype(ref), std::string>::value");
  }
  } // namespace
  