LPC: 25 years of X

These WWS doesn't implement. The lines can be patterned, but if I
remember correctly my code, the pattern is based on the window
co-ordinates (this way the patterns for overlapped elements would match).

Btw. If you test the code, the arc drawing can be a bit buggy, it doesn't
handle all the corner cases (I didn't anymore have that much time for WWS,
and there wasn't really any users for that feature :-)). I've understood
that this was fixed in the Microwindows/Nano-X adaption of the code. They
needed it for their Xlib emulation, so they have tested it properly.

Arc endpoint calculations are done in the client library so that server
doesn't need to do any floating point calculations (a bit similar strategy
to Xft in pushing work to clients that cause the work).