title: CMake find_package not finding Find<package>.cmake
body: <p>I made and installed the aruco library, which put a Findaruco.cmake file in the /usr/local/lib/cmake directory. In my CMakeLists.txt file I have </p>
  
  <pre><code>...
  find_package(aruco REQUIRED)
  </code></pre>
  
  <p>and it always returns the standard error</p>
  
  <pre><code>By not providing "Findaruco.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "aruco", but
  CMake did not find one.
  
  Could not find a package configuration file provided by "aruco" with any of
  the following names:
  
      arucoConfig.cmake
      aruco-config.cmake
  
  Add the installation prefix of "aruco" to CMAKE_PREFIX_PATH or set
  "aruco_DIR" to a directory containing one of the above files.  If "aruco"
  provides a separate development package or SDK, be sure it has been
  installed.
  </code></pre>
  
  <p>I've set the environment variable $CMAKE_PREFIX_PATH to each of the following, and none work</p>
  
  <pre><code>/usr/local  
  /usr/local/lib  
  /usr/local/lib/cmake  
  </code></pre>
  
  <p>The only thing that works is setting the following in CMakeLists</p>
  
  <pre><code>set(CMAKE_MODULE_PATH /usr/local/lib/cmake)
  </code></pre>
  
  <p>I'm not sure what I'm doing wrong</p>