Merge branch 'staging'

Hydra looks very good: https://hydra.nixos.org/eval/1409475?compare=1409440
There's mainly some fallout from aarch64-linux not building `go`
on the first attempt.

pkgs/development/interpreters/python/cpython/2.7/default.nix

@@ -128,7 +128,7 @@ let
     ++ optional hostPlatform.isCygwin expat
     ++ [ db gdbm ncurses sqlite readline ]
     ++ optionals x11Support [ tcl tk xlibsWrapper libX11 ]
-    ++ optionals stdenv.isDarwin [ CF configd ];
+    ++ optionals stdenv.isDarwin ([ CF ] ++ optional (configd != null) configd);
 
   mkPaths = paths: {
     C_INCLUDE_PATH = makeSearchPathOutput "dev" "include" paths;

pkgs/development/libraries/webkitgtk/2.18.nix

@@ -12,7 +12,7 @@ assert enableGeoLocation -> geoclue2 != null;
 with stdenv.lib;
 stdenv.mkDerivation rec {
   name = "webkitgtk-${version}";
-  version = "2.18.1";
+  version = "2.18.2";
 
   meta = {
     description = "Web content rendering engine, GTK+ port";
@@ -42,7 +42,7 @@ stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "http://webkitgtk.org/releases/${name}.tar.xz";
-    sha256 = "15fp7szmkpannx7avsynf0nv3y343qwq0fvq3rz2m2mw5wq7pnww";
+    sha256 = "1ry8zvv6k01g9p7agg326n0ziqpqjxd49h5w1b2is6rjnpqv6k5i";
   };
 
   # see if we can clean this up....