Duncan Coutts
I'd just like to point out (again ;-) ) than it's not that hard to support older platforms. The only constraint is that people not squeal at the sight of bundled code. The bundling can be done in such a way that it's not a maintenance burden, indeed it can remove the need to maintain internal equivalents of external libs.
For example for an external package foo, we could put the latest stable version of it in lib/foo and in the .cabal file say something like:
As the Debian packager, including convenience copies of build dependency libraries in the stable tarballs increases my workload because - Debian Policy requires that I not use them. If the ./configure prefers the convenience copies over the ones found on the system, that means I have to write extra code in debian/rules to force the use of the system copies. - Debian Policy requires that all files in the source tarball -- even libraries that I don't actually compile against -- have their copyright and license information declared in debian/copyright. This means that even if "everybody knows libfoo is GPL", I have to audit the convenience copy to make sure that every significant work (read: file) in the convenience copy has a clear license declaration to that effect, and to document any exceptions. Alternatively, I can create my own stable tarball of darcs by unpacking the one Eric makes, removing the convenience copies, and then re-tarring it. But this is fiddly and normally only done when the upstream tarball contains work that Debian won't or can't (legally) distribute. Therefore while I understand the argument for convenience copies, I'd be obliged if they were kept to a minimum.