--- configure.orig	2012-06-29 22:18:24.000000000 +0900
+++ configure	2012-07-21 16:32:51.000000000 +0900
@@ -2722,6 +2722,7 @@
 
 case $target_cpu in
   i?86) frame_address=yes;;
+  x86_64) frame_address=yes;;
   *)    frame_address=no;;
 esac
 # Check whether --enable-frame-address was given.
@@ -9843,7 +9844,7 @@
 fi
 
 case "$target_cpu" in
-m68*|i?86|ia64|sparc*|alpha*) rb_cv_stack_grow_dir=-1;;
+m68*|i?86|x86_64|ia64|sparc*|alpha*) rb_cv_stack_grow_dir=-1;;
 hppa*) rb_cv_stack_grow_dir=+1;;
 esac
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking stack growing direction" >&5
