diff --git a/CMakeLists.txt b/CMakeLists.txt
index 99b58ebb..ae71905b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -284,11 +284,8 @@ if (MSVC)
 endif()
 if (NOT MSVC)
   add_cxx_compiler_flag("-Wall")
-endif()
-
-if(CMAKE_COMPILER_IS_GNUCXX)
   add_cxx_compiler_flag("-Wextra")
-endif(CMAKE_COMPILER_IS_GNUCXX)
+endif()
 
 add_cxx_compiler_flag("-Wimplicit-fallthrough=2")
 add_cxx_compiler_flag("-Wpointer-arith")