-Wold-style-cast for g++, please ?

[Joe Buck]

> I wouldn't be against this...  I kinda like the idea...  It could be a
> canidate for -Weverything (or whatever it is called).

While we're at it: -Wcast-qual should warn about old-style casts that cast
away const, but not warn about uses of const_cast (since const_cast serves
the function of alerting the reader of the code that const is being cast
away, issuing a warning is redundant).