option (FORCE_COLORED_OUTPUT "Always produce ANSI-colored output (GNU/Clang only)." TRUE)
if (${FORCE_COLORED_OUTPUT})
  if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
    add_compile_options (-fdiagnostics-color=always)
  elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
    add_compile_options (-fcolor-diagnostics)
  endif ()
endif ()