Merge branch 'master' into staging-next

There ver very many conflicts, basically all due to
name -> pname+version.  Fortunately, almost everything was auto-resolved
by kdiff3, and for now I just fixed up a couple evaluation problems,
as verified by the tarball job.  There might be some fallback to these
conflicts, but I believe it should be minimal.

Hydra nixpkgs: ?compare=1538299

pkgs/servers/http/h2o/default.nix

@@ -7,13 +7,13 @@ with builtins;
 
 stdenv.mkDerivation rec {
   pname = "h2o";
-  version = "2.2.5";
+  version = "2.2.6";
 
   src = fetchFromGitHub {
     owner  = "h2o";
     repo   = "h2o";
     rev    = "refs/tags/v${version}";
-    sha256 = "0jyvbp6cjiirj44nxqa2fi5y473gnc8awfn8zv82hb1y9rlxqfyv";
+    sha256 = "0qni676wqvxx0sl0pw9j0ph7zf2krrzqc1zwj73mgpdnsr8rsib7";
   };
 
   # We have to fix up some function prototypes, because despite upstream h2o