diff --git a/tools/cpp/CROSSTOOL.tpl b/tools/cpp/CROSSTOOL.tpl
index 5ef0034..c98ab48 100644
--- a/tools/cpp/CROSSTOOL.tpl
+++ b/tools/cpp/CROSSTOOL.tpl
@@ -969,6 +969,7 @@
       action: 'c++-compile'
       flag_group {
         flag: "/O2"
+        flag: "/DNDEBUG"
       }
     }
   }