title: GCC dependency generation for a different output directory
body: <p>I'm using GCC to generate a dependency file, but my build rules put the output into a subdirectory. Is there a way to tell GCC to put my subdirectory prefix in the dependency file it generates for me?</p>
  
  <pre><code>gcc $(INCLUDES) -E -MM $(CFLAGS) $(SRC) &gt;&gt;$(DEP)
  </code></pre>