Use WM_NCCALCSIZE when drawing window frames on Windows.

When drawing one's own window frame, using WM_NCCALCSIZE, WM_NCPAINT, WM_NCACTIVATE, WM_NCHITTEST, WM_NCMOUSEMOVE, WM_NCLBUTTONDOWN, WM_NCLBUTTONUP etc. the dimensions of that frame differs from windows standard (AdjustWindowRectEx).

To avoid problems like:

• shrinking windows
• layouts that cut things that normally seen, especially when at right or bottom
• miscalculations of window positions, like popup menu isn't straight under the main menu
• mouse cursor is always a few pixel above the things painted

it would be nice if Qt could use WM_NCCALCSIZE instead of AdjustWindowRectEx in QWidgetPrivate::updateFrameStrut()