Bring back LGPLv2 gmp, upgrade gnutls stack

This patch set is the result of gnutls/nettle/gmp license discussion on the mailing list. The end result is that gnutls stack is available as LGPLv2.1 and also as the newest versions (where nettle and gmp are LGPLv3 | GPLv2).

In more detail:
* Re-introduce an older LGPLv2 version of gmp
* Fix nettle binary package license
* Upgrade gnutls and nettle (keep LGPLv2 nettle as well)

gmp 4.2.1 was in better shape than I expected but it's still software that was last updated 9 years ago and is used in a crypto context... If there are other solutions to this problem I'll be happy to hear them out.

Most of the commits depend on the ones before them either via version incompatibilities or via applying on top of each other. I've smoke tested two combinations of versions:
* everything upgraded to newest
* everything at LGPLv2.1 versions

Cheers,
Jussi

The following changes since commit 778fc612cb584d17da02ecc115c4e6edba995602:

libnotify: update to version 0.7.6 (2015-08-26 07:36:15 +0100)

are available in the git repository at:

git://git.yoctoproject.org/poky-contrib jku/lgpl-all-the-things
http://git.yoctoproject.org/cgit.cgi/poky-contrib/log/?h=jku/lgpl-all-the-things

Jussi Kukkonen (6):
nettle: Fix binary license to LGPLv2.1+
gmp: Bring back version 4.2.1 (LGPL 2.1+)
nettle: Add (LGPLv3) version 3.1.1
nettle: Add ptests
gnutls: Upgrade 3.3.14 -> 3.3.17.1
mirrors.bbclass: Update gnutls mirrors

 meta/classes/mirrors.bbclass                       |  5 +-
 .../gmp/gmp-4.2.1/disable-stdc.patch               | 39 +++++++++++++++
 .../gmp/gmp-4.2.1/gmp_fix_for_automake-1.12.patch  | 56 ++++++++++++++++++++++
 .../gmp/{gmp => gmp-6.0.0}/amd64.patch             |  0
 .../append_user_provided_flags.patch               |  0
 .../gmp/{gmp => gmp-6.0.0}/configure.patch         |  0
 .../gmp/{gmp => gmp-6.0.0}/gmp-6.0.0-ppc64.patch   |  0
 .../gmp/{gmp => gmp-6.0.0}/use-includedir.patch    |  0
 meta/recipes-support/gmp/gmp.inc                   | 19 +-------
 meta/recipes-support/gmp/gmp_4.2.1.bb              | 15 ++++++
 meta/recipes-support/gmp/gmp_6.0.0.bb              | 33 ++++++++++---
 .../{gnutls_3.3.14.bb => gnutls_3.3.17.1.bb}       |  4 +-
 ...d-target-to-only-build-tests-not-run-them.patch | 43 +++++++++++++++++
 meta/recipes-support/nettle/files/run-ptest        | 36 ++++++++++++++
 meta/recipes-support/nettle/nettle.inc             | 43 +++++++++++++++++
 meta/recipes-support/nettle/nettle_2.7.1.bb        | 29 ++---------
 meta/recipes-support/nettle/nettle_3.1.1.bb        | 11 +++++
 17 files changed, 276 insertions(+), 57 deletions(-)
 create mode 100644 meta/recipes-support/gmp/gmp-4.2.1/disable-stdc.patch
 create mode 100644 meta/recipes-support/gmp/gmp-4.2.1/gmp_fix_for_automake-1.12.patch
 rename meta/recipes-support/gmp/{gmp => gmp-6.0.0}/amd64.patch (100%)
 rename meta/recipes-support/gmp/{gmp => gmp-6.0.0}/append_user_provided_flags.patch (100%)
 rename meta/recipes-support/gmp/{gmp => gmp-6.0.0}/configure.patch (100%)
 rename meta/recipes-support/gmp/{gmp => gmp-6.0.0}/gmp-6.0.0-ppc64.patch (100%)
 rename meta/recipes-support/gmp/{gmp => gmp-6.0.0}/use-includedir.patch (100%)
 create mode 100644 meta/recipes-support/gmp/gmp_4.2.1.bb
 rename meta/recipes-support/gnutls/{gnutls_3.3.14.bb => gnutls_3.3.17.1.bb} (59%)
 create mode 100644 meta/recipes-support/nettle/files/Add-target-to-only-build-tests-not-run-them.patch
 create mode 100644 meta/recipes-support/nettle/files/run-ptest
 create mode 100644 meta/recipes-support/nettle/nettle.inc
 create mode 100644 meta/recipes-support/nettle/nettle_3.1.1.bb

2.1.4