unbreak SDL 1.2 build. Koda needs to look at this
this brings compatibility up with SDL HEAD (5504), but maybe breaks compatibility with sdl 1.2 so please test! still has problems with keyboard input and rendered ttf textures
I changed r. Still not a perfect fix.
glswapbuffer consistency and create the window in the center (still, it doesn't work past sdl r5296)
Patch for
issue #165: Portal: don't allow embedding Objects in ground (or porting them to impassable/invalid locations)