[SeaBIOS] vgabios: more x86emu issues

[Gerd Hoffmann]

  Hi,

We already have tools/vgafixup.py to workaround some x86emu issues.
Looks like some more is needed, reportly[1] there are more xorg
segfaults which look alot like x86emu isses.  They trigger with stdvga
and qxl (which are handled using the vesa driver), and they only happen
on x86_64 where vm86 mode can not be used to run the vgabios.

Guest in question is RHEL-5 / centos-5.  Xorg version is 1.1.1

Some people digged deep into the x86emu changelogs when this showed up
for the first time.  Anyone remembers the details?  Are there known
x86emu bugs where we don't have workarounds for?

cheers,
  Gerd

[1] https://bugzilla.redhat.com/show_bug.cgi?id=987097