--- ruby-1.8.6/configure.in
+++ patch_for_rubyosx
@@ -1590,14 +1590,15 @@
 AC_SUBST(configure_args)dnl
 
 if test "$fat_binary" != no ; then
-    arch="fat-${target_os}"
 
+    darwin_version=`sysctl -n kern.sysv.shmseg`
+    arch="universal-darwin${darwin_version}.0"
     AC_DEFINE_UNQUOTED(RUBY_THIN_ARCHLIB,
-                 "${RUBY_LIB_PATH}/" __ARCHITECTURE__ "-${target_os}")
+                 "${RUBY_LIB_PATH}/${arch}")
 
     AC_DEFINE_UNQUOTED(RUBY_SITE_THIN_ARCHLIB,
-                 "${RUBY_SITE_LIB_PATH}/" __ARCHITECTURE__ "-${target_os}")
-    AC_DEFINE_UNQUOTED(RUBY_PLATFORM, __ARCHITECTURE__ "-${target_os}")
+                 "${RUBY_SITE_LIB_PATH}/${arch}")
+    AC_DEFINE_UNQUOTED(RUBY_PLATFORM, "${arch}")
 else
     arch="${target_cpu}-${target_os}"
     AC_DEFINE_UNQUOTED(RUBY_PLATFORM, "${arch}")