When the mouse pointer enters the qemu window it takes a pointer grab. This
doesn't sound too dangerous at first but it turns out that SDL will infinitely
busy-loop if it can't get the grab (e.g. if the screen is locked) and the
average autobuilder setup's X server will have locked the screen a few minutes
after boot.
The result is that on many autobuilders apparently random qemu instances (the
top-most one under the pointer) will hang during boot.
To resolve this add an option (via an environment variable) to never attempt a
grab. The default behaviour remains to grab so that everyone else doesn't see
any change.
Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
