title: How to point cmake at specific directory for library?
body: <p>I have a CMake project where I am using a library and now I want to test my code with a different version of that library. I can set INCLUDE_DIRECTORIES (and possibly later also linking) in the below example. But because I only want to do this temporarily, I'd like to manually set this path with ccmake/cmake-gui. </p>
  
  <p>How do I do this?</p>
  
  <pre><code>project(min_example)
  cmake_minimum_required(VERSION 2.8)
  
  find_package(OpenCV REQUIRED)
  # Without the following line please:
  INCLUDE_DIRECTORIES("/home/me/src/opencv/install/include")
  add_executable(min_example main.cpp)
  target_link_libraries(min_example ${OpenCV_LIBS})
  </code></pre>