vtkVariant fails to build gcc 4.9.4 / gcc 4.8.5

ParaView latest master fails to build with GCC-4.9.4 and GCC-4.8.5. This was using the superbuild with the following options:

cmake -G Ninja \
   -DCMAKE_BUILD_TYPE=Release \
   -DENABLE_python=ON \
   -DENABLE_python3=ON \
   -DENABLE_ffmpeg=ON \
   -DENABLE_qt5=ON \
   -Dqt5_SOURCE_SELECTION=5.12 \
   -DENABLE_ospray=ON \
   -Dparaview_SOURCE_SELECTION=git \
   ../paraview-superbuild

[20/18069] Building CXX object VTK/Common/Core/CMakeFiles/CommonCore.dir/vtkVariant.cxx.o
FAILED: VTK/Common/Core/CMakeFiles/CommonCore.dir/vtkVariant.cxx.o 
/opt/jenkins/jenkins-tools/gcc-4.9.4/bin/g++ -DCommonCore_EXPORTS -DVTK_MODULE_ENABLE_VTK_loguru=1 -IVTK/Common/Core -I/opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Common/Core -IVTK/Common/Core/../DataModel -IVTK/ThirdParty/loguru/vtkloguru -I/opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/ThirdParty/loguru/vtkloguru -isystem VTK/Utilities/KWIML -isystem /opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Utilities/KWIML -isystem VTK/Utilities/KWSys -isystem /opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Utilities/KWSys -isystem VTK/ThirdParty/utf8 -isystem /opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/ThirdParty/utf8 -isystem VTK/ThirdParty/loguru -isystem /opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/ThirdParty/loguru -isystem /opt/jenkins/workspace/build1/install/include -fPIC    -std=c++11  -O3 -DNDEBUG -fPIC -fvisibility=hidden -fvisibility-inlines-hidden -pthread -std=c++11 -MD -MT VTK/Common/Core/CMakeFiles/CommonCore.dir/vtkVariant.cxx.o -MF VTK/Common/Core/CMakeFiles/CommonCore.dir/vtkVariant.cxx.o.d -o VTK/Common/Core/CMakeFiles/CommonCore.dir/vtkVariant.cxx.o -c /opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Common/Core/vtkVariant.cxx
/opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Common/Core/vtkVariant.cxx: In function ‘std::ios_base& (* GetFormattingFunction(int))(std::ios_base&)’:
/opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Common/Core/vtkVariant.cxx:667:14: error: ‘hexfloat’ is not a member of ‘std’
       return std::hexfloat;
              ^
/opt/jenkins/workspace/build1/superbuild/paraview/src/VTK/Common/Core/vtkVariant.cxx:671:14: error: ‘defaultfloat’ is not a member of ‘std’
       return std::defaultfloat;
              ^
[21/18069] Building CXX object VTK/Common/Transforms/CMakeFiles/CommonTransforms.dir/vtkHomogeneousTransform.cxx.o

/cc @mwestphal