Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/\${ <-- HERE ([^ \t=:+{}]+)}/ at xxxx/usr/bin/automake line 3939.

/**********************************************************************
 *    Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/${ <-- HERE ([^ \t=:+{}]+)}/ at xxxx/usr/bin/automake line 3939.
 * 说明：
 *     在Ubuntu 18.04上编译Yocto，出现的automake正则表达式问题。原因是Perl
 * 不支持以前的写法。
 *
 *                                2018-6-13 深圳 宝安西乡 曾剑锋
 *************************************************************************************************************