I’m happy to report that since then I’ve installed SXCE, and things are going much more smoothly under it. OpenSolaris (2008.05) is for the time being relegated to a VirtualBox, where its quirks are pretty much harmless. SXCE seems to be a much more stable platform to work on.
That also means I can now build the SFW (Sun Freeware) consolidation, and thus work within Sun’s development environment. Which was basically the goal of the exercise. I’ve navigated my way around it just enough to integrate one of my own Apache modules, which now successfully builds and generates a package.
This is still not an environment I’d choose to work in: the SFW consolidation is huge and unwieldy, and its build is an epic several-hour job. I need to figure out at least how to sync my work with the repository rather than use giant tarballs. But at least I’m now able to do Sun work in its primary target environment of Sun’s webstack (which is part of SFW).