Actually you can use CLion with Unreal Engine 4. I’ve looked through some posts and found some answers:
CLion Source Accessor:
There is still big problem with cmake file. I’ve writter a small blog post about changin CMakeFileGenerator to work with CLion. That should work on OS X and, I hope, Linux.
You may change it a bit if you want to make it work on windows. I wish I could publish this changes in public fork, but unfortunately, GitHub doesn’t allow to create public forks.