GitLab

Merge initial readback/offscreen stuff

See merge request laagocs/qtrhi!1

not yet implemented

...in a console app.

only implemented for Vulkan for now

...and related plumbing here and there.

This reverts commit 2676ad23.

Now passing --metallib (or -t) to qsb will transparently generate
a metallib binary, storing that instead of the MSL source. The rhi
backend picks it then up automatically, when present.

...and so using pre-compiled byecode transparently to the applications.