(byte shared_object) linking mode does not allow linking C stubs

[nojb]

From #7789 (comment):

Actually, I misremembered: it is possible to build a shared_object out of bytecode by using (modes (byte shared_object)), sorry for the confusion (this is explained in the manual: https://dune.readthedocs.io/en/latest/dune-files.html#linking-modes

Not exactly. (byte shared_object) doesn't allow to link C stubs:

74 | (executable
75 |  (name xxx)
76 |  (modes (byte shared_object))
....
95 |  )
96 |  (flags)
97 | )
Error: Pure bytecode executables cannot contain foreign stubs.
Hint: If you only need to build a native executable use "(modes exe)".

Interestingly, (modes shared_object) works with ocamlc for an executable with C stubs (when ocamlopt is not available). Maybe the error above is just a bug?