title: Flycheck - disabling Clang as a checker *permanently*
body: <p>I use Flycheck to check C files, and have a fairly elaborate variable setup for GCC to allow it to work correctly. However, due to having Clang on my system (for reasons unrelated to code), Flycheck always assumes that this is what I want to use, forcing me to manually switch checkers all the time. </p>
  
  <p>I've tried to look for a way to permanently disable Clang as a checker, but I've come up empty. Help would be appreciated.</p>