Ensure CMAKE_OSX_* variable are passed to all projects.

See #418

CMakeLists.txt

@@ -33,10 +33,10 @@ include(ctkMacroCheckExternalProjectDependency)
 if(APPLE)
   # Note: By setting CMAKE_OSX_* variables before any enable_language() or project() calls,
   #       we ensure that the bitness will be properly detected.
-  include(${CMAKE_SOURCE_DIR}/CMake/ctkBlockSetCMakeOSXVariables.cmake)
+  include(ctkBlockSetCMakeOSXVariables)
   mark_as_superbuild(
     VARS CMAKE_OSX_ARCHITECTURES:STRING CMAKE_OSX_SYSROOT:PATH CMAKE_OSX_DEPLOYMENT_TARGET:STRING
-    PROJECTS CTK
+    ALL_PROJECTS
     )
 endif()