[ros-dev] Partial build (newbie question)

[Mad Alchemist]

Hello! I already have almost latest trunk build of ReactOS installed. 
Now I want to try
modifying some sources, but recompiling whole system takes about 8 hours 
on my
very slow PC. How can I recompile only modified part of the system?
I am using RosBE for Linux version 1.5.