Without this commit, the following test was failing:

  VTK_SOURCE_DIR=~/Projects/VTK
  VTK_BUILD_DIR=/home/jcfr/Projects/VTK-Release

  rm -rf vtkLocalStandalone*
  cp -r $VTK_SOURCE_DIR/Examples/Build/vtkLocal/ vtkLocalStandalone
  pushd vtkLocalStandalone
  for file in $(ls -1); do
    updated_file=$(echo $file | sed -e 's/vtkLocal/vtkLocalStandalone/g');
    sed -e 's/vtkLocal/vtkLocalStandalone/g' -i $file
    sed -e 's/VTKLOCAL/VTKLOCALSTANDALONE/g' -i $file
    [[ $file != $updated_file ]] && mv $file $updated_file
  done
  popd

  mkdir vtkLocalStandalone-build
  pushd vtkLocalStandalone-build

  cmake -DVTK_DIR:PATH=$VTK_BUILD_DIR ../vtkLocalStandalone
  make -j4

  popd

with error:

  CMake Error at /home/jcfr/Projects/VTK/CMake/vtkModuleMacros.cmake:505 (export):
    export FILE option given filename "" which does not have an extension of
    ".cmake".

  Call Stack (most recent call first):
    /home/jcfr/Projects/VTK/CMake/vtkModuleMacros.cmake:547 (vtk_target_export)
    /home/jcfr/Projects/VTK/CMake/vtkModuleMacros.cmake:624 (vtk_target)
    /home/jcfr/Projects/VTK/CMake/vtkModuleMacros.cmake:712 (vtk_add_library)
    CMakeLists.txt:28 (vtk_module_library)

Suggested-by: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>