New decision method to enable Fortran tests

CMake does not enable Fortran for its own build, but it needs to find a
Fortran compiler to know if it is possible to enable Fortran tests.
Previously we searched for a hard-coded list of Fortran compilers which
was duplicated from the CMakeDetermineFortranCompiler.cmake module.  We
now run CMake on a small test project that enables the Fortran language
and reports the compiler it found.  This represents a more realistic
check of whether the Fortran tests will be able to find a compiler.

Modules/CMakeDetermineFortranCompiler.cmake

@@ -62,9 +62,6 @@ IF(NOT CMAKE_Fortran_COMPILER)
     #  The order is 95 or newer compilers first, then 90, 
     #  then 77 or older compilers, gnu is always last in the group,
     #  so if you paid for a compiler it is picked by default.
-    # NOTE for testing purposes this list is DUPLICATED in
-    # CMake/Source/CMakeLists.txt, IF YOU CHANGE THIS LIST,
-    # PLEASE UPDATE THAT FILE AS WELL!
     SET(CMAKE_Fortran_COMPILER_LIST
       ifort ifc efc f95 pgf95 lf95 xlf95 fort gfortran gfortran-4 g95 f90
       pgf90 xlf90 epcf90 fort77 frt pgf77 xlf fl32 af77 g77 f77

Tests/CMakeLists.txt

@@ -1472,17 +1472,9 @@ ${CMake_BINARY_DIR}/bin/cmake -DVERSION=CVS -P ${CMake_SOURCE_DIR}/Utilities/Rel
 
   # fortran does not work for IDE builds because
   # CMAKE_STANDARD_LIBRARIES needs to be per language
-  IF(CMAKE_TEST_GENERATOR MATCHES "Makefiles"
-     OR CMAKE_TEST_GENERATOR MATCHES "KDevelop")
-    # see if we can find a fortran compiler on the machine
-    # if so, add the fortran test and see if it works.
-    SET(CMAKE_Fortran_COMPILER_LIST ifort ifc efc f95 pgf95
-      lf95 xlf95 fort gfortran gfortran-4 f90  pgf90   xlf90
-      epcf90 f77  fort77 frt pgf77  xlf  fl32 af77 g77  )
-    FIND_PROGRAM(CMAKE_Fortran_COMPILER_FULLPATH NAMES 
-      ${CMAKE_Fortran_COMPILER_LIST} )
-    MARK_AS_ADVANCED(CMAKE_Fortran_COMPILER_FULLPATH)
-    IF(CMAKE_Fortran_COMPILER_FULLPATH)
+  IF(CMAKE_TEST_GENERATOR MATCHES "Make|KDevelop")
+    INCLUDE(${CMAKE_CURRENT_SOURCE_DIR}/CheckFortran.cmake)
+    IF(CMAKE_Fortran_COMPILER)
       ADD_TEST(Fortran ${CMAKE_CTEST_COMMAND}
         --build-and-test
         "${CMake_SOURCE_DIR}/Tests/Fortran"
@@ -1493,9 +1485,8 @@ ${CMake_BINARY_DIR}/bin/cmake -DVERSION=CVS -P ${CMake_SOURCE_DIR}/Utilities/Rel
         --build-two-config
         --test-command testf)
       LIST(APPEND TEST_BUILD_DIRS "${CMake_BINARY_DIR}/Tests/Fortran")
-    ENDIF(CMAKE_Fortran_COMPILER_FULLPATH)
-  ENDIF(CMAKE_TEST_GENERATOR MATCHES "Makefiles"
-     OR CMAKE_TEST_GENERATOR MATCHES "KDevelop")
+    ENDIF()
+  ENDIF()
 
   IF(NOT CMAKE_TEST_GENERATOR MATCHES "Xcode")
     INCLUDE(FindJava)

Tests/CheckFortran.cmake

@@ -0,0 +1,45 @@
+
+#=============================================================================
+# Copyright 2009 Kitware, Inc.
+#
+# Distributed under the OSI-approved BSD License (the "License");
+# see accompanying file Copyright.txt for details.
+#
+# This software is distributed WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the License for more information.
+#=============================================================================
+# (To distributed this file outside of CMake, substitute the full
+#  License text for the above reference.)
+
+if(NOT DEFINED CMAKE_Fortran_COMPILER)
+  set(_desc "Looking for a Fortran compiler")
+  message(STATUS ${_desc})
+  file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran/CMakeLists.txt"
+    "cmake_minimum_required(VERSION 2.4)
+project(CheckFortran Fortran)
+file(WRITE \"\${CMAKE_CURRENT_BINARY_DIR}/result.cmake\"
+  \"set(CMAKE_Fortran_COMPILER \\\"\${CMAKE_Fortran_COMPILER}\\\")\\n\")
+")
+  execute_process(
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran
+    COMMAND ${CMAKE_COMMAND} . -G ${CMAKE_GENERATOR}
+    OUTPUT_VARIABLE output
+    ERROR_VARIABLE output
+    RESULT_VARIABLE result
+    )
+  include(${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles/CheckFortran/result.cmake OPTIONAL)
+  if(CMAKE_Fortran_COMPILER AND "${result}" STREQUAL "0")
+    file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
+      "${_desc} passed with the following output:\n"
+      "${output}\n")
+  else()
+    set(CMAKE_Fortran_COMPILER NOTFOUND)
+    file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+      "${_desc} failed with the following output:\n"
+      "${output}\n")
+  endif()
+  message(STATUS "${_desc} - ${CMAKE_Fortran_COMPILER}")
+  set(CMAKE_Fortran_COMPILER "${CMAKE_Fortran_COMPILER}" CACHE FILEPATH "Fortran compiler")
+  mark_as_advanced(CMAKE_Fortran_COMPILER)
+endif()