on of the gflags package and find it using CMake's find_package
command, or include the gflags project as subtree or submodule within your project's source tree and add the directory
using CMake's add_subdirectory command.
    
<p>To use an external gflags installation, add the following CMake code to your <code>CMakeLists.txt</code> file.</p>

<p>Find gflags installation. The <code>gflags_DIR</code> variable must be set to the &lt;prefix&gt;/lib/cmake/gflags directory
containing the gflags-config.cmake fil