title: ./configure unable to find header files
body: <p>I'm compiling a project that uses SDL_mixer to play <code>.ogg</code> files. However, <code>Mix_Init(MIX_INIT_OGG)</code> fails, and <code>Mix_GetError()</code> returns <code>"Mixer not built with Ogg Vorbis support"</code>. The version of SDL_mixer I'm using is 1.2.12, downloaded via Homebrew.</p>
  
  <p>So I downloaded the sources for SDL_mixer (same version, 1.2.12), and tried building it with Ogg support, i.e. <code>./configure --enable-music-ogg</code>, but <code>configure</code> is unable to find the Vorbis header files. This is the output it's giving:</p>
  
  <pre><code>checking vorbis/vorbisfile.h usability... no
  checking vorbis/vorbisfile.h presence... no
  checking for vorbis/vorbisfile.h... no
  checking for ov_open_callbacks in -lvorbisfile... no
  configure: WARNING: *** Unable to find Ogg Vorbis library (http://www.xiph.org/)
  configure: WARNING: Ogg Vorbis support disabled
  </code></pre>
  
  <p>I even tried passing <code>--includedir=/usr/local/include</code> to <code>configure</code>, without success. I have both the Vorbis and Ogg header files in <code>/usr/local/include</code>, so e.g. the path to <code>vorbisfile.h</code> is <code>/usr/local/include/vorbis/vorbisfile.h</code>. I also tried building both libogg and libvorbis from scratch, but I still get the same errors. I'm using OS X 10.11.1 beta.</p>
  
  <p>What am I doing wrong?</p>
  
  <hr>
  
  <p><strong>Edit</strong></p>
  
  <p>Output of <code>brew ls sdl_mixer</code>:</p>
  
  <pre><code>/usr/local/Cellar/sdl_mixer/1.2.12/include/SDL/SDL_mixer.h
  /usr/local/Cellar/sdl_mixer/1.2.12/lib/libSDL_mixer-1.2.0.dylib
  /usr/local/Cellar/sdl_mixer/1.2.12/lib/pkgconfig/SDL_mixer.pc
  /usr/local/Cellar/sdl_mixer/1.2.12/lib/ (2 other files)
  </code></pre>