Please make the build reproducible

[apoleon]

There is an ongoing effort to make builds reproducible.

https://wiki.debian.org/ReproducibleBuilds

Here is a patch to achieve that for bam.

https://gist.github.com/apoleon/d00da5d3f87a1f76f766ad8b0f6f0c08

[matricks]

This was fixed a while back.