title: What is bogus_type in C
body: <p>I've been going through some types defined in libgcc. They are all apparently mapped to the same type named <code>bogus_type</code>. I can not find its definition. </p>
  
  <pre><code>#define SItype bogus_type
  #define USItype bogus_type
  #define DItype bogus_type
  #define UDItype bogus_type
  #define SFtype bogus_type
  #define DFtype bogus_type
  </code></pre>
  
  <p>What does this type map to? Is it even a valid type or something like <code>NULL</code>?</p>