add_subdirectory(common) if (CMAKE_SYSTEM_NAME MATCHES "Darwin") add_subdirectory(macosx) elseif (CMAKE_SYSTEM_NAME MATCHES "Linux") add_subdirectory(linux) elseif (CMAKE_SYSTEM_NAME MATCHES "FreeBSD") add_subdirectory(freebsd) elseif (CMAKE_SYSTEM_NAME MATCHES "Windows") add_subdirectory(windows) endif()