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/mail/opensmtpd/default.nix

@@ -4,14 +4,14 @@
 
 stdenv.mkDerivation rec {
   pname = "opensmtpd";
-  version = "6.4.1p2";
+  version = "6.4.2p1";
 
   nativeBuildInputs = [ autoconf automake libtool bison ];
   buildInputs = [ libasr libevent zlib libressl db pam ];
 
   src = fetchurl {
     url = "https://www.opensmtpd.org/archives/${pname}-${version}.tar.gz";
-    sha256 = "0cppqlx4fk6l8rbim5symh2fm1kzshf421256g596j6c9f9q96xn";
+    sha256 = "0pgv080ai7d98l9340jadp9wjiaqj2qvgpqhilcz0kps2mdiawbd";
   };
 
   patches = [