diff --git a/configure.in b/configure.in
index 3cdb8c9d8..ed905049c 100644
--- a/configure.in
+++ b/configure.in
@@ -58,7 +58,7 @@ AC_ARG_ENABLE(debug,
   *)   AC_MSG_RESULT(yes)
 
     CPPFLAGS="$CPPFLAGS -DMALLOCDEBUG"
-    CFLAGS="-Wall -pedantic -g" 
+    CFLAGS="-W -Wall -Wwrite-strings -pedantic -g" 
        ;;
   esac ],
        AC_MSG_RESULT(no)