added script for re-running autoconf/automake et. al.

git-svn-id: https://svn.apache.org/repos/asf/xerces/c/trunk@469112 13f79535-47bb-0310-9956-ffa450edef68

reconf

+#!/bin/sh
+set -x
+rm -f config.cache
+aclocal -I m4
+autoheader
+automake -a
+autoconf
+exit
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