Module build failed (from ./node_modules/postcss-loader/src/index.js):
15:31:24.560 TypeError: Cannot read property 'prefix_exceptions' of undefined
15:31:24.566 at Browsers.prefix (E:\smct\student\node_modules\autoprefixer\lib\browsers.js:76:23)
15:31:24.567 at E:\smct\student\node_modules\autoprefixer\lib\prefixes.js:174:31
15:31:24.574 at Array.map (<anonymous>)
15:31:24.574 at _loop (E:\smct\student\node_modules\autoprefixer\lib\prefixes.js:173:31)
15:31:24.582 at Prefixes.select (E:\smct\student\node_modules\autoprefixer\lib\prefixes.js:198:7)
15:31:24.594 at new Prefixes (E:\smct\student\node_modules\autoprefixer\lib\prefixes.js:98:49)
15:31:24.595 at loadPrefixes (E:\smct\student\node_modules\autoprefixer\lib\autoprefixer.js:102:20)
15:31:24.603 at plugin (E:\smct\student\node_modules\autoprefixer\lib\autoprefixer.js:109:20)
15:31:24.604 at LazyResult.run (E:\smct\student\node_modules\postcss\lib\lazy-result.js:295:14)
15:31:24.616 at LazyResult.asyncTick (E:\smct\student\node_modules\postcss\lib\lazy-result.js:208:26)
15:31:24.617 at E:\smct\student\node_modules\postcss\lib\lazy-result.js:213:17
这是报错信息，browsers.js找不到prefix_exceptions变量，怎么配置postcss.config.js文件才行
