title: Homebrew and CMake package registry
body: <p>I'm writing cmake scripts for packages with which I would like to use <a href="https://cmake.org/cmake/help/v3.3/manual/cmake-packages.7.html#package-registry" rel="nofollow">CMake's package registry feature</a>. I would also like to make my scripts work nicely with <a href="http://brew.sh" rel="nofollow">OS X's Homebrew</a> which likes to install packages into its Cellar directories like <code>/usr/local/Cellar/cisstnetlib/HEAD/cmake</code>.</p>
  
  <p>Generally Homebrew tries to keep the build and install pretty isolated, while the CMake registry requires creating files in <code>/Users/username/.cmake/packages/CisstNetlib/CisstNetlib</code>.</p>
  
  <p>I'm interested in a reliable way to write the brew script and the CMake script so that they will work together easily, make use of the CMake package registry, while maintaining compatibility and ease of use of the CMake scripts on other platforms such as linux and windows.</p>