Problems with QVariant and some undefined functions on Linux...

Fixes for libfamitracker and nesicide
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2 small changes here:
- QVariant has ctor overloads for `int`, `unsigned int`, `qlonglong` (`long long int`) and `qulonglong` (`unsigned long long int`), but no `unsigned long int` overload. As a result, (implicit) calls to QVariant ctor with `UINT_PTR` arguments are ambiguous. Fix: those problematic implicit ctor calls cast the `UINT_PTR` value to `uint_ptr`, a typedef hidden in a namespace `qtmfc_workaround`; `uint_ptr` is `unsigned int` or `qulonglong` depending on the size of `UINT_PTR`;
- Commented-out calls to `ShellExecute` and `TrackMouseEvent`: they are currently undefined.

Sorry for the noise.