add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backports/optional)

list(APPEND ASY_STATIC_LIBARIES OptionalBackport)

if (ENABLE_OPENGL)
   add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/backports/glew)
   # using glew within the repo
   list(APPEND ASY_STATIC_LIBARIES GLEW)

   list(APPEND ASYMPTOTE_INCLUDES $<TARGET_PROPERTY:GLEW,INCLUDE_DIRECTORIES>)
endif()