iOS needs a back key as well due to lack of hardware buttons.
At least until a gesture can replace this function.
glClearColor(0,0,0,1);
Add glClearColor(0,0,0,1);
Merge pull request #766 from raven02/patch-1

glClearColor(0,0,0,1);
Initial implementation of vf2h.

Fixes Fat Princess and possibly other stuff.
Correct prefix handling in vf2h/vh2f.