Some more refactoring might not be totally useless

most differences in Eva oracles come from the fact that now anonymous arguments are taken into
account when generating default assigns for prototypes with empty specs.

Avoid warning about missing proto during typechecking.
Also changes a warning into an error, and improves the error message.

- Fix Value/Value#5
- Fix Value/Value#14

Some case studies (e.g. dyad) use some ugly casts from fd_set_t which lead
to the analysis stopping too early.
Changing the representation of fd_set_t should also help it better conform to
the standard (since a fd_set_t should be able to hold FD_SETSIZE elements).

[Ptests] preserve LOG after STDOPT directive

See merge request frama-c/frama-c!2073

This is absolutely not a sneaky attempt to relaunch a build (now that OCI seems
in better shape) pushing a nearly empty commit.