message: Fix gcc 5.4.0 compiling error.
  The isnan() is not in global namespace.
diff: @@ -12,11 +12,11 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
  ==============================================================================*/
  -#include <math.h>
  #include <stdint.h>
  #include <stdlib.h>
  #include <algorithm>
  +#include <cmath>
  #include <initializer_list>
  #include <limits>
  #include <map>
  @@ -1900,7 +1900,7 @@ TEST(FloatActivationsOpTest, Softmax1DInf) {
  m.Invoke();
  auto output = m.GetOutput();
  for (int i = 0; i < 8; ++i) {
  - EXPECT_TRUE(isnan(output[i]));
  + EXPECT_TRUE(std::isnan(output[i]));
  }
  }
  