BUG: Fix for issue #5193. Base result of FindMFC.cmake mostly on a TRY_COMPILE result. Gives accurate answer about whether MFC is available.

Modules/FindMFC.cmake

@@ -1,19 +1,47 @@
 # - Find MFC on Windows
-# Find the native MFC - i.e. decide if this is an MS VC box.
+# Find the native MFC - i.e. decide if an application can link to the MFC
+# libraries.
 #  MFC_FOUND - Was MFC support found
 # You don't need to include anything or link anything to use it.
 
 # Assume no MFC support
-SET( MFC_FOUND "NO" )
-# Add MFC support if win32 and not cygwin and not borland
-IF( WIN32 )
-  IF( NOT CYGWIN )
-    IF( NOT BORLAND )
-      IF( NOT MINGW )
-        SET( MFC_FOUND "YES" )
-      ENDIF( NOT MINGW )
-    ENDIF( NOT BORLAND )
-  ENDIF( NOT CYGWIN )
-ENDIF( WIN32 )
+SET(MFC_FOUND "NO")
 
+# Only attempt the try_compile call if it has a chance to succeed:
+SET(MFC_ATTEMPT_TRY_COMPILE 0)
+IF(WIN32 AND NOT UNIX AND NOT BORLAND AND NOT MINGW)
+  SET(MFC_ATTEMPT_TRY_COMPILE 1)
+ENDIF(WIN32 AND NOT UNIX AND NOT BORLAND AND NOT MINGW)
 
+IF(MFC_ATTEMPT_TRY_COMPILE)
+  IF("MFC_HAVE_MFC" MATCHES "^MFC_HAVE_MFC$")
+    SET(CHECK_INCLUDE_FILE_VAR "afxwin.h")
+    CONFIGURE_FILE(${CMAKE_ROOT}/Modules/CheckIncludeFile.cxx.in
+      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckIncludeFile.cxx)
+    MESSAGE(STATUS "Looking for MFC")
+    TRY_COMPILE(MFC_HAVE_MFC
+      ${CMAKE_BINARY_DIR}
+      ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/CheckIncludeFile.cxx
+      CMAKE_FLAGS
+      -DCMAKE_MFC_FLAG:STRING=2
+      -DCOMPILE_DEFINITIONS:STRING=-D_AFXDLL
+      OUTPUT_VARIABLE OUTPUT)
+    IF(MFC_HAVE_MFC)
+      MESSAGE(STATUS "Looking for MFC - found")
+      SET(MFC_HAVE_MFC 1 CACHE INTERNAL "Have MFC?")
+      FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
+        "Determining if MFC exists passed with the following output:\n"
+        "${OUTPUT}\n\n")
+    ELSE(MFC_HAVE_MFC)
+      MESSAGE(STATUS "Looking for MFC - not found")
+      SET(MFC_HAVE_MFC 0 CACHE INTERNAL "Have MFC?")
+      FILE(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
+        "Determining if MFC exists failed with the following output:\n"
+        "${OUTPUT}\n\n")
+    ENDIF(MFC_HAVE_MFC)
+  ENDIF("MFC_HAVE_MFC" MATCHES "^MFC_HAVE_MFC$")
+
+  IF(MFC_HAVE_MFC)
+    SET(MFC_FOUND "YES")
+  ENDIF(MFC_HAVE_MFC)
+ENDIF(MFC_ATTEMPT_TRY_COMPILE)