Index: configure.in
===================================================================
--- configure.in.orig
+++ configure.in
@@ -1757,7 +1757,12 @@ case "$target_os" in
     rubyw_install_name="$RUBYW_INSTALL_NAME"
     ;;
 esac
-RUBY_LIB_PREFIX=`eval echo \\"${libdir}/ruby\\"`
+
+AC_ARG_WITH(rubylibdir,
+	    [  --with-rubylibdir=DIR      stdlib libraries in DIR [[LIBDIR/ruby]]],
+            [rubylibdir=$withval],
+            [rubylibdir='${libdir}/ruby'])
+RUBY_LIB_PREFIX=`eval echo \\"${rubylibdir}\\"`
 
 AC_ARG_WITH(sitedir,
 	    [  --with-sitedir=DIR      site libraries in DIR [[LIBDIR/ruby/site_ruby]]],