autoreconf invoked to build desauto

I think `./configure` is invoked as part of https://github.com/gap-packages/guava/blob/master/Makefile.in#L24 to simplify the build instructions (you can run just `make` rather than `cd src/leon; ./configure; cd ../..; make`). But I can't explain the `autoreconf`? I've been using the supplied `./configure` script for a while now without issues (by patching out the `autoreconf`).
