[PATCH] user32/msgbox: Implement copying contents to clipboard

[Fabian Maurer]

FWIW, that's bug https://bugs.winehq.org/show_bug.cgi?id=17205
A staging patchset is available at https://github.com/wine-staging/wine-staging/tree/master/patches/user32-msgbox-Support-WM_COPY-mesg

Regards,
Fabian Maurer