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/development/libraries/xxHash/default.nix

@@ -2,13 +2,13 @@
 
 stdenv.mkDerivation rec {
   pname = "xxHash";
-  version = "0.7.0";
+  version = "0.7.1";
 
   src = fetchFromGitHub {
     owner = "Cyan4973";
     repo = "xxHash";
     rev = "v${version}";
-    sha256 = "19iyr7x0s7in9kp9wrj4iimdx58nv6jndz9x5ndnl07gd90y7jxb";
+    sha256 = "0hh1ypwk86m3b0x4433k95f94b48kvl7s79dml0f3g0cv8jdvkgw";
   };
 
   outputs = [ "out" "dev" ];