--- a/configure.ac
+++ b/configure.ac
@@ -1375,7 +1375,7 @@ AS_IF([test -n "$GCC"], [
         AS_IF([test "x$with_optim" != x], [
             OPTIM="$with_optim $OPTIM"
         ], [
-            OPTIM="-Os $OPTIM"
+            OPTIM=" $OPTIM"
         ])
     ])