Fixed: Compilation with old CMake versions

--HG--
branch : develop

code/CMakeModules/PCHSupport.cmake

@@ -176,10 +176,21 @@ MACRO(PCH_SET_COMPILE_FLAGS _target)
   ENDIF()
 
   IF(CMAKE_VERSION VERSION_LESS "3.3.0")
-    GET_DIRECTORY_PROPERTY(_directory_flags DEFINITIONS)
+    GET_DIRECTORY_PROPERTY(_DIRECTORY_FLAGS DEFINITIONS)
-    GET_DIRECTORY_PROPERTY(_directory_definitions DIRECTORY ${CMAKE_SOURCE_DIR} DEFINITIONS)
+
-    LIST(APPEND _FLAGS ${_directory_flags})
+    IF(_DIRECTORY_FLAGS)
-    LIST(APPEND _FLAGS ${_directory_definitions})
+      FOREACH(item ${_DIRECTORY_FLAGS})
+        LIST(APPEND _FLAGS "$<$<BOOL:${item}>:-D$<JOIN:${item},-D>>")
+      ENDFOREACH()
+    ENDIF()
+    
+    GET_DIRECTORY_PROPERTY(_DIRECTORY_DEFINITIONS DIRECTORY ${CMAKE_SOURCE_DIR} DEFINITIONS)
+
+    IF(_DIRECTORY_DEFINITIONS)
+      FOREACH(item ${_DIRECTORY_DEFINITIONS})
+        LIST(APPEND _FLAGS "$<$<BOOL:${item}>:-D$<JOIN:${item},-D>>")
+      ENDFOREACH()
+    ENDIF()
   ENDIF()
 
   # Format definitions