gallium: wrap u_screen in extern "C" for c++
Some drivers (notabily SWR) are written in C++, and as such they need access to C headers with extern "C". So lets add that.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
Some drivers (notabily SWR) are written in C++, and as such they need access to C headers with extern "C". So lets add that.