title: Kernel Configuration Fragment not applying
body: <p>I am attempting to add a linux kernel configuration fragment file (<code>linux-1024MB-frags.config</code>) into my build. Inside the fragment file I have set, <code>CONFIG_HIGHMEM=y</code>. </p>
  
  <p>In my buildroot .config I have enabled,</p>
  
  <p><code>BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="$(BR2_EXTERNAL_MYPATH)/board/common/linux-1024MB-frags.config"</code></p>
  
  <p>When I do <code>linux-dirclean &amp;&amp; linux-configure</code> I see the following output, </p>
  
  <pre><code>Merging /home/labuser/buildroot/trunk/board/common/linux-1024MB-frags.config
  #
  # merged configuration written to /home/labuser/buildroot/trunk/buildroot/output/build/linux-xilinx-v2017.1/.config (needs make)
  #
  </code></pre>
  
  <p>Inspecting the new .config file shows that <code>CONFIG_HIGHMEM</code> is still not set. </p>
  
  <p>If I set <code>CONFIG_HIGHMEM</code> in the main defconfig that I am using for the kernel (the one defined by <code>BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE</code>) and repeat the make steps I see that the <code>CONFIG_HIGHMEM</code> option IS set.</p>