I know I've been promising this since more or less the dawn of time, but it's finally now real - the top of tree in CVS is now building!
That's not to say it necessarily works, of course. :) There's still a fair few changes to be made, and bugs to be fixed as a result of those changes, but at least there's progress.
My new policy is to require head of tree to build, always. I'll be checking that myself before each commit. If anyone nonetheless finds that it doesn't build straight out of head of tree, drop me a line and I'll fix it pronto.
In future major development will proceed in branches, merging back to the main trunk only when complete (or at least building).