cmake HAS_PARENT_PATH examples

tmp64/BugfixedHL-Rebased gamedir/CMakeLists.txt :102 

cmake_path( HAS_PARENT_PATH rel_file_path has_parent_path )

twhl-community/halflife-unified-sdk CMakeLists.txt :29 

cmake_path(HAS_PARENT_PATH CMAKE_INSTALL_PREFIX HAS_HALFLIFE_DIRECTORY)