Index: /OpenSceneGraph/trunk/CMakeLists.txt
===================================================================
--- /OpenSceneGraph/trunk/CMakeLists.txt (revision 9757)
+++ /OpenSceneGraph/trunk/CMakeLists.txt (revision 9770)
@@ -579,5 +579,12 @@
 # This will only be made available if we set values for OSG_AGGRESSIVE_WARNING_FLAGS.
 IF(OSG_AGGRESSIVE_WARNING_FLAGS)
-    OPTION(OSG_USE_AGGRESSIVE_WARNINGS "Enable to activate aggressive warnings" ON)
+
+    IF (APPLE)
+        SET(DEFAULT_USE_AGGRESSIVE_WARNINGS OFF)
+    ELSE(APPLE)
+        SET(DEFAULT_USE_AGGRESSIVE_WARNINGS ON)
+    ENDIF(APPLE)
+
+    OPTION(OSG_USE_AGGRESSIVE_WARNINGS "Enable to activate aggressive warnings" ${DEFAULT_USE_AGGRESSIVE_WARNINGS})
     MARK_AS_ADVANCED(OSG_USE_AGGRESSIVE_WARNINGS)