The logical clause and the pre-state are now optional. The function can now
be used to remove from a state all inferred properties that depend on a given
memory location.
This only impacts the cvalue domain, which is the only one to use the assign
clause.

Queries return an origin option instead of an origin.
Domains not using the origin simply return None, and no longer need to define
the origin type.

Uses [memo] from State_builder.Option_ref.
Also stores the maximum size of the allocated bases once for all, instead of
calling [Bit_utils.max_bit_adddress] in various places.

- Function contracts: remove abrupt clauses from the list of exceptions
- Statement contracts: remove abrupt clauses from the list of exceptions
- Add grammar for abrupt termination
- Update list of contributors

When a builtin expects a void pointer (as argument or result), any pointer type
is accepted.
This allows allocation builtins to be used for more functions.

... so that varinfo and logic_var stay synchronized.

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

According to the kernel option -warn-invalid-pointer.

Complies with the kernel option -warn-invalid-pointers.