gnupg-2.1.11 on x86_64 failed its tests many times on Hydra:

  http://hydra.gnu.org:3000/build/990803#tabs-buildsteps

On all other architectures (i686, armhf, mips64el) it succeeded on the
first try.  So far, we've heard no reports of it failing for anyone else
on x86_64.  Ludovic built it 3 times on his x86_64 machine and it never
failed.

It failed in at least two different ways:

* With only 1 test failure: gpgtar.test.  This happened on at least two
  different build slaves.

* With 14 test failures.  This happened at least twice, on
  hydra.gnunet.org.

I've attached 4 of the failure logs retrieved from Hydra.  There are two
logs of each of the two failure modes described above.

It would be good to understand what happened here.

     Mark