diff --git a/CMakeLists.txt b/CMakeLists.txt
index b8f9a03e7..d5352fa80 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -189,6 +189,9 @@ append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_WNO_LONG_LONG_FLAG -Wno-long-long)
 if (LIBCXX_ENABLE_WERROR)
   append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_WERROR_FLAG -Werror)
   append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_WX_FLAG -WX)
+else()
+  append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_WNO_ERROR_FLAG -Wno-error)
+  append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_NO_WX_FLAG -WX-)
 endif()
 if (LIBCXX_ENABLE_PEDANTIC)
   append_if(LIBCXX_CXX_WARNING_FLAGS LIBCXX_HAS_PEDANTIC_FLAG -pedantic)
diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 977acdc26..f0219c091 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -13,9 +13,11 @@ check_cxx_compiler_flag(-Wwrite-strings       LIBCXX_HAS_WWRITE_STRINGS_FLAG)
 check_cxx_compiler_flag(-Wno-long-long        LIBCXX_HAS_WNO_LONG_LONG_FLAG)
 check_cxx_compiler_flag(-pedantic             LIBCXX_HAS_PEDANTIC_FLAG)
 check_cxx_compiler_flag(-Werror               LIBCXX_HAS_WERROR_FLAG)
+check_cxx_compiler_flag(-Wno-error            LIBCXX_HAS_WNO_ERROR_FLAG)
 check_cxx_compiler_flag(-fno-exceptions       LIBCXX_HAS_FNO_EXCEPTIONS_FLAG)
 check_cxx_compiler_flag(-fno-rtti             LIBCXX_HAS_FNO_RTTI_FLAG)
 check_cxx_compiler_flag(/WX                   LIBCXX_HAS_WX_FLAG)
+check_cxx_compiler_flag(/WX-                  LIBCXX_HAS_NO_WX_FLAG)
 check_cxx_compiler_flag(/EHsc                 LIBCXX_HAS_EHSC_FLAG)
 check_cxx_compiler_flag(/EHs-                 LIBCXX_HAS_NO_EHS_FLAG)
 check_cxx_compiler_flag(/EHa-                 LIBCXX_HAS_NO_EHA_FLAG)