And this brings back the question of what to do with autoconf. I would really, really like to have one that is 100% compatible with our (and others) configure.in-files but then goes through all the normal steps of parsing, generating an abstract tree, optimize it and then generate, with language plugins, the configure files. Two given plugins would be sh and pike.
Or, the less advanced but still usable route of forking autoconf and maintain a compatible, optimized version with actual enhancements from 2.5x backported.