[Intel-gfx] [PATCH i-g-t] igt: Make dependency on libunwind mandatory

[Chris Wilson]

Quoting Arkadiusz Hiler (2017-12-01 13:19:54)
> With Android support gone there is not much reason for keeping libunwind
> dependency optional. This also deals (cheaply!) with ifdefs covering
> huge portions of code, removing a placement minefield.

Could also force building with frame-pointers? I'm wonder if that would
help with the less-than-useful stacktraces I get...
-Chris