Fix Mac error when building qgis_app

Author: dakcarto

src/app/CMakeLists.txt

@@ -481,6 +481,10 @@ TARGET_LINK_LIBRARIES(qgis_app
   qgis_analysis
 )
 
+IF (APPLE)
+  TARGET_LINK_LIBRARIES(qgis_app ${APP_SERVICES_LIBRARY})
+ENDIF(APPLE)
+
 if(MSVC AND CMAKE_SIZEOF_VOID_P EQUAL 8)
   SET_TARGET_PROPERTIES(qgis_app PROPERTIES STATIC_LIBRARY_FLAGS "/machine:x64")
 ENDIF(MSVC AND CMAKE_SIZEOF_VOID_P EQUAL 8)