[Bug libstdc++/83755] Pretty printers treat char* as NTBS

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83755

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
We can prevent this by always casting the stored pointer to void*

        self.pointer = self.pointer.cast(gdb.lookup_type("void").pointer())