title: Show #pragma message in header only once during build
body: <p>I have a bunch of <code>#pragma message("A message")</code>s in a <code>config.h</code> header that gets included in many places in the project; the goal is to inform which configuration options are chosen during build. The header is protected by <code>#ifndef #define</code> style headerguards. The problem is that every time this header gets included, the message is printed. Is there a better way to do this so that the message gets printed only once during the build?</p>
  
  <p><strong>Edit:</strong> I understand that build options are usually manipulated and viewed with build tools such as cmake, qmake, autotools etc. but I don't really have a choice on the build tools due to the nature of the project.</p>