Netlify deploy failing about gatsby-mdx-netlify-cms-starter HOT 1 CLOSED

This is a hack but the issue is MDX run time, and you need to set node: { fs: 'empty' } in gatsby-confg.js. See here:

mdx-js/mdx#913
webpack-contrib/css-loader#447 (comment)
gatsbyjs/gatsby#10326 (comment) <- this is the issue, but you need to modify the plugins config NOT your local config, they are separate. here is the hack below:

{
      resolve: `gatsby-plugin-netlify-cms`,
      options: {
        modulePath: `${__dirname}/src/cms/cms.js`, // for custom preview in the Netlify CMS
        customizeWebpackConfig: (config) => (config.node.fs = 'empty'),
      },
    }

from gatsby-mdx-netlify-cms-starter.