HEADSUP: all MirageOS unikernel compilations are broken right now

[Hannes Mehnert <hannes@xxxxxxxxxxx>]

Dear everyone,

first of all: Happy New Year! :)

since lwt 6.0.0 came into existance, unfortunately all MirageOS 
unikernel compilations (for any target apart from unix) are broken.
The issue is that lwt now uses
```
 (libraries
 (select lwt_rte.ml from
  (lwt_runtime_events -> lwt_rte.with.ml)
  (-> lwt_rte.without.ml))))
```

Which interacts badly with dune / solo5 cross-compilation. I opened an 
issue at the dune issue tracker https://github.com/ocaml/dune/issues/13299
Any help is appreciated. I've no experience with dune, and do not 
understand how MirageOS unikernels are compiled (when typing `make 
build`) well enough.

We, well, Reynir, discovered that while working on DNSvizor 
https://github.com/robur-coop/dnsvizor/pull/116
Best,

Hannes