The https://reproducible-builds.org project invests a lot of work
to make builds reproducible. This is a security property. It allows
to compare the build of binaries from different builder machines.
If they are identical, it means that either the builds have not
been manipulated or an attacker managed to attack all builder
machines in exactly the same way.
One problem that the reproducible-builds project often sees is
that projects include the build time in their binaries. This
makes builds unreproducible for apparently no reason. The build
date should not be of interest since binaries built on different
dates but from the same source code should not be different.
Thus I decided to remove the build date instead of re-implementing
the functionality without the GitRev task. Anyways the reported
date was not the build date but the date of the last git commit
which is even less informative. The git commit ID would have
information value but should only be relevant for "nightly builds".