There are three problems reported by you.
1. The line-smooth issue. It's hard to point out where the problem is without any codes. Did it work several months ago? Could you please try to narrow down the problem and send it to me?
2. The gl_FrontFacing problem. It should be fixed in Cat11.5 and you have to wait for a few days.
3. The sign of dFdy. I think it works in the driver. The sign is positive only when a render buffer is attached to the FBO. If you have the problem, please also send the program to me.
My email address is firstname.lastname@example.org. Thanks for your feedback.