message: Export list of TPL include directories
  The default CMake targets file exports all of the TPL library linkage
  necessary, but we weren't exporting the include directories. Now we
  are.
diff: @@ -219,6 +219,7 @@ foreach(TPL IN LISTS MFEM_TPLS)
  if (${TPL}_FOUND)
  message(STATUS "MFEM: using package ${TPL}")
  list(APPEND TPL_LIBRARIES ${${TPL}_LIBRARIES})
  + list(APPEND TPL_INCLUDE_DIRS ${${TPL}_INCLUDE_DIRS})
  endif()
  endforeach(TPL)
  @@ -406,8 +407,11 @@ export(TARGETS ${PROJECT_NAME}
  # with a global CMake-registry)
  export(PACKAGE ${PROJECT_NAME})
  +# Extract the include directories required to use MFEM
  +get_target_property(MFEM_TPL_INCLUDE_DIRS mfem INCLUDE_DIRECTORIES)
  +
  # This is the build-tree version
  -set(INCLUDE_INSTALL_DIRS ${PROJECT_BINARY_DIR})
  +set(INCLUDE_INSTALL_DIRS ${PROJECT_BINARY_DIR} ${MFEM_TPL_INCLUDE_DIRS})
  set(LIB_INSTALL_DIR ${PROJECT_BINARY_DIR})
  configure_package_config_file(config/cmake/MFEMConfig.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}/MFEMConfig.cmake
  @@ -415,7 +419,7 @@ configure_package_config_file(config/cmake/MFEMConfig.cmake.in
  PATH_VARS INCLUDE_INSTALL_DIRS LIB_INSTALL_DIR)
  # This is the version that will be installed
  -set(INCLUDE_INSTALL_DIRS ${INSTALL_INCLUDE_DIR})
  +set(INCLUDE_INSTALL_DIRS ${INSTALL_INCLUDE_DIR} ${MFEM_TPL_INCLUDE_DIRS})
  set(LIB_INSTALL_DIR ${INSTALL_LIB_DIR})
  configure_package_config_file(config/cmake/MFEMConfig.cmake.in
  ${CMAKE_CURRENT_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/MFEMConfig.cmake
  