Comment 0 for bug 1949553

[Impact]

These are needed for 20.04.4 images.

[Test case]

Boot a daily image, see that it still has the necessary stack installed and working.

[What could go wrong]

libdrm: adds some new api, no changes to old stuff

llvm-13: a new package, no regression potential on it's own

mesa: a new major release, but we'll pull the final stable release of 21.2.x series, so there shouldn't be any regressions left at that point

xserver: a new point-release, 1.20.x series is in deep maintenance mode, so there should be little chance of breakage