--- configure.orig	2012-02-15 12:59:36.000000000 +0900
+++ configure	2012-02-18 14:31:46.000000000 +0900
@@ -15215,8 +15215,8 @@
 fi
 
 if test -n "$GCC"; then
-   CFLAGS="-O3 -Wall";
-   CXXFLAGS="-O3 -Wall";
+   CFLAGS="$CFLAGS -Wall";
+   CXXFLAGS="$CXXFLAGS -Wall";
 fi