Still working on reproducible builds

The announcement email for the initial release of SBCL suggests that build bootstrapping (related to reproducibility) was one of the main reasons for the fork from CMUCL: http://jcsu.jesus.cam.ac.uk/~csr21/sbcl-0.0.

Even if your build process doesn't involve bootstrapping the implementation language, reproducible builds seem like a difficult but desirable thing: https://news.ycombinator.com/item?id=8023035.