diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index a48da5aa2..44be14326 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -618,7 +618,7 @@ IF(BUILD_TESTING)
   ENDIF (CTEST_TEST_CTEST)
   # see if we can find a fortran compiler on the machine
   # if so, add the fortran test and see if it works.
-  INCLUDE(CMakeDetermineFortranCompiler OPTIONAL)
+  INCLUDE(${CMake_SOURCE_DIR}/Modules/CMakeDetermineFortranCompiler.cmake)
   IF(CMAKE_Fortran_COMPILER_FULLPATH)
     ADD_TEST(Fortran ${CMAKE_CTEST_COMMAND}
       --build-and-test