GDK W32: Another massive clipboard and DnD update
Rename GdkWin32Selection to GdkWin32Clipdrop, since GdkSelection is mostly gone, and the word "selection" does not reflect the functionality of this object too well. Clipboard is now handled by a separate thread, most of the code for it now lives in gdkclipdrop-win32.c, gdkclipboard-win32.c just uses clipdrop as a backend. The DnD source part is also put into a thread. The DnD target part does not spin the main loop, it just emits a GDK event and returns a default value if it doesn't get a reply by the time the event is processed. Both clipboard and DnD use a new GOutputStream subclass to get data from GTK and put it into a HGLOBAL. GdkWin32DragContext is split into GdkWin32DragContext and GdkWin32DropContext, anticipating a similar change that slated to happen to GdkDragContext. OLE2 DnD protocol is now used by default, set GDK_WIN32_OLE2_DND envvar to 0 to make GDK use the old LOCAL and DROPFILES protocols. https://bugzilla.gnome.org/show_bug.cgi?i...