There are sure regressions but basic stuff seems to be working
again after all the API breakage done with comments like
"Win32 and Quartz need to be ported still."
This function makes a better replacement for
gdk_display_get_core_pointer(), wherever it might yet be needed, for
XI2 resorts to XIGetClientPointer(), for the others return the only
core pointer.
https://bugzilla.gnome.org/show_bug.cgi?id=621685