title: Device tree compiler not recognizes C syntax for include files
body: <p>I want to compile my board device tree manually. I have downloaded the latest version of <code>dtc</code> from its official <a href="https://git.kernel.org/pub/scm/utils/dtc/dtc.git" rel="noreferrer">source</a>, but when I try to run the following command, I get an error advising me to change all <code>#include</code> directives to <code>/include/</code> and so on for <code>#define</code> , etc.</p>
  <pre><code>dtc -I dts -O dtb -p 0x1000 meson-gxl-s905x-khadas-vim.dts -o kvim1.dtb
  </code></pre>
  <p>My board is Khadas Vim with an amlogic S905x SoC in its heart. All include files are present and the error is:</p>
  <pre><code>Error: meson-gxl-s905x-khadas-vim.dts:8.1-9 syntax error
  FATAL ERROR: Unable to parse input tree
  </code></pre>
  <p>The 8th line is:</p>
  <pre><code>#include &lt;dt-bindings/input/input.h&gt;
  </code></pre>
  <p>Changing the <code>#include</code> to <code>/include/</code> will suppress the error!</p>
  <p>If you know some reference for device tree 'language' (except U-boot documentations) , introduce it please.</p>