1. This mutation is never observed outside the function.
2. If it were (it's not), it would be undefined behaviour, since the
packet data goes out of scope a few instructions after the callback
returns.
- Any non-externally-visible declarations should be `static`.
- Casting away the `const` qualifier from pointers-to-const is
dangerous. All but one instance of this are now correct. The one
instance where we can't keep `const` is one where toxav code actually
writes to a chunk of memory marked as `const`. This code also assumes
4 byte alignment of data packets. I don't know whether that is a valid
assumption, but it's likely unportable, and *not* obviously correct.
- Replaced empty parameter lists with `(void)` to avoid passing
parameters to it. Empty parameter lists are old style declarations for
unknown number and type of arguments.
- Commented out (as `#if DHT_HARDENING` block) the hardening code that
was never executed.
- Minor style fix: don't use `default` in enum-switches unless the number
of enumerators in the default case is very large. In this case, it was
2, so we want to list them both explicitly to be warned about missing
one if we add one in the future.
- Removed the only two function declarations from nTox.h and put them
into nTox.c. They are not used outside and nTox is not a library.
This removes the global logger (which by the way was deleted when the first tox
was killed, so other toxes would then stop logging). Various bits of the code
now carry a logger or pass it around. It's a bit less transparent now, but now
there is no need to have a global logger, and clients can decide what to log and
where.
