clean FindUmfpack.cmake wrt enable_language(Fortran)

cmake/FindUmfpack.cmake

diff --git a/cmake/FindUmfpack.cmake b/cmake/FindUmfpack.cmake
index 4f6875a..d76f5df 100644
--- a/cmake/FindUmfpack.cmake
+++ b/cmake/FindUmfpack.cmake
@@ -3,55 +3,58 @@
   set(UMFPACK_FIND_QUIETLY TRUE)
 endif (UMFPACK_INCLUDES AND UMFPACK_LIBRARIES)
 
-enable_language(Fortran)
-find_package(BLAS)
+if(CMAKE_Fortran_COMPILER_WORKS)
 
-if(BLAS_FOUND)
+  find_package(BLAS)
 
-find_path(UMFPACK_INCLUDES
-  NAMES
-  umfpack.h
-  PATHS
-  $ENV{UMFPACKDIR}
-  ${INCLUDE_INSTALL_DIR}
-  PATH_SUFFIXES
-  suitesparse
-)
+  if(BLAS_FOUND)
 
-find_library(UMFPACK_LIBRARIES umfpack PATHS $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
+  find_path(UMFPACK_INCLUDES
+    NAMES
+    umfpack.h
+    PATHS
+    $ENV{UMFPACKDIR}
+    ${INCLUDE_INSTALL_DIR}
+    PATH_SUFFIXES
+    suitesparse
+  )
 
-if(UMFPACK_LIBRARIES)
+  find_library(UMFPACK_LIBRARIES umfpack PATHS $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
 
-  get_filename_component(UMFPACK_LIBDIR ${UMFPACK_LIBRARIES} PATH)
+  if(UMFPACK_LIBRARIES)
 
-  find_library(AMD_LIBRARY amd PATHS ${UMFPACK_LIBDIR} $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
-  if (AMD_LIBRARY)
-    set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${AMD_LIBRARY})
-  else (AMD_LIBRARY)
-    set(UMFPACK_LIBRARIES FALSE)
-  endif (AMD_LIBRARY)
+    get_filename_component(UMFPACK_LIBDIR ${UMFPACK_LIBRARIES} PATH)
 
-endif(UMFPACK_LIBRARIES)
+    find_library(AMD_LIBRARY amd PATHS ${UMFPACK_LIBDIR} $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
+    if (AMD_LIBRARY)
+      set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${AMD_LIBRARY})
+    else (AMD_LIBRARY)
+      set(UMFPACK_LIBRARIES FALSE)
+    endif (AMD_LIBRARY)
 
-if(UMFPACK_LIBRARIES)
+  endif(UMFPACK_LIBRARIES)
 
-  find_library(COLAMD_LIBRARY colamd PATHS ${UMFPACK_LIBDIR} $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
-  if (COLAMD_LIBRARY)
-    set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${COLAMD_LIBRARY})
-  else (COLAMD_LIBRARY)
-    set(UMFPACK_LIBRARIES FALSE)
-  endif (COLAMD_LIBRARY)
+  if(UMFPACK_LIBRARIES)
 
-endif(UMFPACK_LIBRARIES)
+    find_library(COLAMD_LIBRARY colamd PATHS ${UMFPACK_LIBDIR} $ENV{UMFPACKDIR} ${LIB_INSTALL_DIR})
+    if (COLAMD_LIBRARY)
+      set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${COLAMD_LIBRARY})
+    else (COLAMD_LIBRARY)
+      set(UMFPACK_LIBRARIES FALSE)
+    endif (COLAMD_LIBRARY)
 
-if(UMFPACK_LIBRARIES)
-  set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${BLAS_LIBRARIES})
-endif(UMFPACK_LIBRARIES)
+  endif(UMFPACK_LIBRARIES)
 
-endif(BLAS_FOUND)
+  if(UMFPACK_LIBRARIES)
+    set(UMFPACK_LIBRARIES ${UMFPACK_LIBRARIES} ${BLAS_LIBRARIES})
+  endif(UMFPACK_LIBRARIES)
 
-include(FindPackageHandleStandardArgs)
-find_package_handle_standard_args(UMFPACK DEFAULT_MSG
-                                  UMFPACK_INCLUDES UMFPACK_LIBRARIES)
+  endif(BLAS_FOUND)
+
+endif(CMAKE_Fortran_COMPILER_WORKS)
+
+  include(FindPackageHandleStandardArgs)
+  find_package_handle_standard_args(UMFPACK DEFAULT_MSG
+                                    UMFPACK_INCLUDES UMFPACK_LIBRARIES)
 
 mark_as_advanced(UMFPACK_INCLUDES UMFPACK_LIBRARIES AMD_LIBRARY COLAMD_LIBRARY)

test/CMakeLists.txt

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index bec17e6..55d1369 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -25,6 +25,7 @@
   message("CHOLMOD not found, this optional backend won't be tested")
 endif(CHOLMOD_FOUND)
 
+enable_language(Fortran OPTIONAL)
 find_package(Umfpack)
 if(UMFPACK_FOUND)
   add_definitions("-DEIGEN_UMFPACK_SUPPORT")