A patch to fix some compiler warnings in qwt

[Uwe]

warnings about C casts ...

Well warnings about that casts are casting - even if the compiler offers to enable such warnings they doesn't make much sense to me. And enabling additional warning levels for compiling 3rd party libraries doesn't seem to be something that a user needs to do.

Anyway, the reason for these warnings is because Qwt still uses C casts instead of C++ casts. This decsision was made because of compiler limitations 10 years ago. This should be pointless nowadays and Qt itself uses C++ casts.

I will replace all C casts.

There's also one about QwtPlotZoomer::move()

This one is indeed worth a warning as the compiler can't identify the right move method from the parameter type, when one of them has been overloaded. I will change this.

uncertain choice of overload in QDebug operator<<( QDebug debug, const QwtScaleMap &map )

When you mean the missing enum to int cast - I will add it.

Uwe