title: Why is clang-tidy not getting its options set through ALE?
body: <p>I'm able to run clang-tidy with my source file <code>clang-tidy -p build/compile_commands.json filename.h</code> and it works as expected. When I open the file through vim I get errors with the first #includes, which happens if I leave the <code>-p</code> option off the invocation. </p>
  
  <p>In my vimrc I tried setting <code>g:ale_c_build_dir</code> to <code>build</code> and that didn't work, so I tried setting <code>g:ale_cpp_clangtidy_extra_options</code> with the <code>-p</code> argument above and that didn't work. I'm able to confirm that these values are being set properly with <code>ALEInfo</code>, they're just not being used in the clang-tidy invocation apparently.</p>