* All platforms additionally require the development versions of the following
  software packages installed.
    * SDL (http://www.libsdl.org/download-1.2.php)
    * SDL_image (http://www.libsdl.org/projects/SDL_image/)
    * libpng (http://www.libpng.org/pub/png/libpng.html)
    * Freetype 2 (http://www.freetype.org/download.html)

* The Linux and Mac OS X builds additionally require libpng.  The Mac OS X
  version expects it to be installed via fink in /sw.  If this is not the
  case, then you should edit PNG_INCLUDE and PNG_LIB in makefile.x11.

  On Mac OS X, these are expected to be installed via fink in /sw.  On Linux,
  these can be installed via a package manager.  On Windows, they should be
  installed, compiled, and the headers and libs placed in a location that the
  compiler can find them via its default include and library paths.