diff --git a/CMakeLists.txt b/CMakeLists.txt
index ef5564e20..db3892ca1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -273,11 +273,13 @@ if(ENABLE_RTI)
 endif(ENABLE_RTI)
 
 if(CMAKE_COMPILER_IS_GNUCXX)
-    set(WARNING_FLAGS -Wall)
+    set(WARNING_FLAGS_CXX "-Wall")
+    set(WARNING_FLAGS_C   "-Wall")
 endif(CMAKE_COMPILER_IS_GNUCXX)
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang") 
-   set (WARNING_FLAGS "-Wall -Wno-overloaded-virtual")
+   set (WARNING_FLAGS_CXX "-Wall -Wno-overloaded-virtual")
+   set (WARNING_FLAGS_C   "-Wall")
 endif() 
 
 if(WIN32)
@@ -297,8 +299,8 @@ if(WIN32)
     set(NOMINMAX 1)
 endif(WIN32)
 
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WARNING_FLAGS} ${MSVC_FLAGS} -D_REENTRANT")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${WARNING_FLAGS} ${MSVC_FLAGS} -D_REENTRANT")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${WARNING_FLAGS_C} ${MSVC_FLAGS} -D_REENTRANT")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${WARNING_FLAGS_CXX} ${MSVC_FLAGS} -D_REENTRANT")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${MSVC_LD_FLAGS}")
 
 include_directories(${OPENSCENEGRAPH_INCLUDE_DIRS}