Kerbel Space Program, and perhaps some other SDL-based programs, use
a really dumb way of specifying icons, which is totally
non-standards-compliant.
The ICCCM specifies that the icon_pixmap field of WM_HINTS should be a
1-bit-deep Pixmap, but we've seen applications set it to a pixmap of the
root depth as well, so we support that.
Kerbel Space Program seems to use it with a 32-bit depth Pixmap,
signifying ARGB32 (which it is), along with a 1-bit icon_mask, which
crashes us.
Keep in mind that Pixmaps, by definition, have no Visual attached, so
we simply have to make a guess at the correct visual based on the
depth. Do that by assuming that a depth-32 visual always means ARGB32,
which is a pretty safe bet.
This is specifically about managing X11 windows, not necessarily
running as an X11 compositor. By that I mean that this code is
still used for XWayland windows, and event handling is still and
modesetting / monitor management is still in core/.
This is also a fairly conservative move. We don't move anything
like screen.c or bell.c in here, even though those are really
only for X11 clients.
