json-c: update to 0.12, fixing CVE-2013-{6370,6371}
pam: upstream patch to fix CVE-2014-2583
qwt: add version 6.x (we already have 5.x)

'qgis', one of the few 'qwt' dependees in nixpkgs, fails to build with
qwt 6. So I'm not moving the default version away from 5.x. Also, not
changing the default allows easy/safe cherry-picking to the stable
branch.
Remove obsolete Agda-executable package; the compiler is not part of 'Agda'.
HTTP-4000.2.13: jailbreak to fix build with latest version of conduit

https://github.com/haskell/HTTP/issues/61
https://github.com/NixOS/nixpkgs/issues/2495
haskell-HTTP-4000.2.13: disable test suite to fix the build

https://github.com/haskell/HTTP/issues/60