Attached patch is for the immediate issue - it's enough to make the build in question to pass. It's likely to leave at least theoretical ways for the build to proceed so that version header is not generated in time.
Has a textual dependency on #43579
In one environment I'm getting build failures with the meson because various places that try to include "version_gen.h", and it has not yet been generated (i.e. we have nothing dictating the build order so that it would be built before anything that requires it, except for the obvious common library)