(I25) Fix Xproto deprecation warnings

I made the ```enterLeave::ELFlagFocus``` and ```enterLeave::ELFlagSameScreen``` fields in ```__gshared``` const int because I think it's the closest to a C representation of the struct. 
Sorry, that's wrong. The declarations are struct fields right now, `__gshared` makes them data-segment globals. Still, an `enum` would be more appopriate.