Merge staging into closure-size

The most complex problems were from dealing with switches reverted in
the meantime (gcc5, gmp6, ncurses6).
It's likely that darwin is (still) broken nontrivially.

pkgs/development/libraries/rdkafka/default.nix

@@ -1,14 +1,13 @@
 { stdenv, fetchFromGitHub, zlib, perl }:
 
 stdenv.mkDerivation rec {
-  name = "rdkafka-${version}";
-  version = "0.8.6";
+  name = "rdkafka-2015-11-03";
 
   src = fetchFromGitHub {
     owner = "edenhill";
     repo = "librdkafka";
-    rev = version;
-    sha256 = "0iklvslz35dd0lz26ffrbfb20qirl9v5kcdmlcnnzc034hr2zmnv";
+    rev = "3e1babf4f26a7d12bbd272c1cdf4aa6a44000d4a";
+    sha256 = "1vmbbkgdwxr25wz60hi6rhqb843ipz34r9baygv87fwh3lwwkqwl";
   };
 
   buildInputs = [ zlib perl ];