SunView support

[waywardmonkeys]

There's code scattered here and there in Maiko to support SunView.

This was a windowing system that was from the days before X11 that was available on Sun hardware up through SunOS 4. Sun ended up switching away, going on a path through Open Windows and eventually to only X11.

This wasn't available on SunOS 5 / Solaris. There was an XView that was similar, but I don't think it has been maintained in 15 years or more.

There was also a library, pixrect, which was available on SunOS 4 and didn't get carried through to Solaris. We have some code using this, but guarded by an ifdef.

We no longer build or support any SunOS 4 systems, so all of this is a bunch of legacy that we don't maintain and complicates a number of code paths.

Is there anything special or important that was only implemented for SunView, that we wouldn't want to lose as a reference?