--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -53,12 +53,6 @@
   endif(WIN32)
 endif(UNIX)
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -Wall -fPIC -O2")
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g -Wall -fPIC -O2")
-if (RELEASE)
-  add_definitions(-O2 -DNDEBUG)
-endif(RELEASE)
-
 # --------------------------------------------------------------
 #  yaml.core
 # --------------------------------------------------------------