Auto merge of #3554 - bmwiedemann:patch-1, r=alexcrichton
authorbors <bors@rust-lang.org>
Fri, 20 Jan 2017 18:48:12 +0000 (18:48 +0000)
committerbors <bors@rust-lang.org>
Fri, 20 Jan 2017 18:48:12 +0000 (18:48 +0000)
make build reproducible

see https://reproducible-builds.org/ for why this is good
and https://wiki.debian.org/ReproducibleBuilds/TimestampsProposal#Bash_.2F_POSIX_shell for variants that also work on BSD


Trivial merge