title: Warning: ISO C forbids an empty translation unit
body: <p>In a header file I have the following code which gives me the error in the title, while trying to link.</p>
  
  <pre><code>#ifndef BOOLEAN_H
  #define BOOLEAN_H
  
  #ifndef FALSE
  #define FALSE 0
  #endif
  
  #ifndef TRUE
  #define TRUE !FALSE
  #endif
  
  #endif
  
  indicating the error occurs in the line of the last #endif 
  </code></pre>