Quick & easy stopgap for CVE-2014-3689: We just compile out the
hardware acceleration functions which lack sanity checks. Thankfully
we have capability bits for them (SVGA_CAP_RECT_COPY and
SVGA_CAP_RECT_FILL), so guests should deal just fine, in theory.
Subsequent patches will add the missing checks and re-enable the
hardware acceleration emulation.