There's openra.net which is an open source "all the Command and Conquer games" engine, which may be of interest?

Runs quite well with WINE using CnCnet.

Im addicted to general zero hour, you can buy the cnc collection on steam and it runs fine.

I wish EA wasn't so shit at programming, it crashes if you minimize the window. Or has a mismatch if theres to many units on the ground.

Theres mods to fix issues, but i cant figure out how to make it work under wine.

EA also open sourced the code and people are working on fixing bugs