Custom Sitecore ConfigReader to allow setting custom include folder locations

ConfigReader.cs

using System.Configuration;
using System.Xml;
using Sitecore;
using Sitecore.Configuration;
using Sitecore.Diagnostics;

namespace MyProject.Custom
{
    class ConfigReader : Sitecore.Configuration.ConfigReader
    {
        protected override void LoadAutoIncludeFiles(XmlNode element)
        {
            Assert.ArgumentNotNull((object)element, "element");

            base.LoadAutoIncludeFiles(element);

            string customFolder = ConfigurationManager.AppSettings["Sitecore.Include.Custom"];
            ConfigPatcher configPatcher = this.GetConfigPatcher(element);
            this.LoadAutoIncludeFiles(configPatcher, MainUtil.MapPath(customFolder));
        }
    }
}

Web.Config

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="sitecore" type="MyProject.Custom.ConfigReader, MyProject.Custom" />
    ...
  </configSections>
  <appSettings>
    <add key="Sitecore.Include.Custom" value="/App_Config/Custom_Include" />
    ...
  </appSettings>
...