diff --git a/src/osgPlugins/cfg/CMakeLists.txt b/src/osgPlugins/cfg/CMakeLists.txt
index 070f4d005..972675ffc 100644
--- a/src/osgPlugins/cfg/CMakeLists.txt
+++ b/src/osgPlugins/cfg/CMakeLists.txt
@@ -1,4 +1,4 @@
-SET(TARGET_SRC 
+SET(TARGET_SRC
   CameraConfig.cpp
   Camera.cpp
   ConfigLexer.cpp
@@ -16,19 +16,26 @@ SET(TARGET_H
   VisualChooser.h
 )
 
+
+
+# lex/yacc generated files use register that causes warnings with CLang under OSX so disable this warnings.
+IF(${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")
+   SET(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -Wno-deprecated-register)
+ENDIF()
+
 #
-# Android NDK r6, r6b and r7 ship with a broken gcc (armeabi) 
-# see also 
-# - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40836 
+# Android NDK r6, r6b and r7 ship with a broken gcc (armeabi)
+# see also
+# - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40836
 # - http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37987
 #
 if (ANDROID)
-    set_source_files_properties(ConfigParser.cpp 
+    set_source_files_properties(ConfigParser.cpp
         PROPERTY
         COMPILE_FLAGS
         "-O0")
 endif()
-# 
+#
 
 SET(TARGET_ADDED_LIBRARIES osgViewer)