message: make glfw dependency required
diff: @@ -26,7 +26,7 @@ set(CMAKE_CXX_STANDARD 17)
  ## Find dependencies ##
  find_package(OpenGL REQUIRED)
  -find_package(glfw3)
  +find_package(glfw3 REQUIRED)
  set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
  set(THREADS_PREFER_PTHREAD_FLAG TRUE) # for gcc6
  find_package(Threads REQUIRED)
  