See https://github.com/yquake2/yquake2/issues/71
and https://github.com/yquake2/xatrix/issues/4
In ClientThink(), the float value ent->velocity[i]*8 is saved into
a short and if the value is too big for a short, in 32bit gcc builds
the short is set to SHRT_MIN, resulting in the player being pressed
down instead of up.
Now we put the result in a 32bit int first (which should be big enough)
and assign the int to the short. This still overflows, but with -fwrapv
at least in a defined way (most probably the same way the original
binaries did).
The Makefile now sets $CC to gcc for MingW builds, this should fix
https://github.com/yquake2/xatrix/issues/3
And while I was at it, when the game lib is loaded, it prints the date
it was built, this is especially interesting for our Win32 binaries.
