With any port's to dreamcast, you have to think of 16 meg main memory if the game use's more then that it's going to be very hard to get running. Not much point porting it dreamcast if it cant fit into memory..
When posting i like to port this or that please include memory usage
Straight C is best C++ work's but not fully ..
Anyway's Null porting a game or emulator, to dreamcast is not that hard. it's writing the render code and sound code. That's why SDL was so good at the time.
If there is a SDL version of decent, i'm sure it could be ported. Still memory leak's EG SDL openbor engine show, the trouble there ...