The reason why gst-libav is broken on x86_64

[Mark H Weaver]

FYI, I investigated the problem with gst-libav on x86_64, and it turns
out that it began when we updated nettle from 2.7 to 3.1, the latter of
which is configured with --enable-fat.  For details, see my post on
bug-nettle:

  http://lists.lysator.liu.se/pipermail/nettle-bugs/2015/003389.html

We could work around the problem by removing the --enable-fat configure
option, although it will entail a lot of rebuilding.  While we're at it,
we should also update to nettle-3.1.1.

      Mark