Clutter 1.7.x introduced CLUTTER_CAIRO_FORMAT_ARGB32: which can be used when
sharing textures/data with cairo without having to do check the
byte order and choose the appropriate format by hand.
https://bugzilla.gnome.org/show_bug.cgi?id=654577
Like all X API, XFixesGetCursorImage returns arrays of 32-bit
quantities as arrays of long; on 64-bit systems we need to
convert to an array of 32-bit words before creating a texture
from the result.
https://bugzilla.gnome.org/show_bug.cgi?id=633591
