Merge branch 'master' into staging

Resolved the following conflicts (by carefully applying patches from the both
branches since the fork point):

   pkgs/development/libraries/epoxy/default.nix
   pkgs/development/libraries/gtk+/3.x.nix
   pkgs/development/python-modules/asgiref/default.nix
   pkgs/development/python-modules/daphne/default.nix
   pkgs/os-specific/linux/systemd/default.nix

pkgs/stdenv/generic/check-meta.nix

@@ -144,7 +144,7 @@ let
     homepage = either (listOf str) str;
     downloadPage = str;
     license = either (listOf lib.types.attrs) (either lib.types.attrs str);
-    maintainers = listOf str;
+    maintainers = listOf (attrsOf str);
     priority = int;
     platforms = listOf str;
     hydraPlatforms = listOf str;

pkgs/stdenv/linux/make-bootstrap-tools.nix

@@ -88,7 +88,7 @@ in with pkgs; rec {
     '' else throw "unsupported libc for bootstrap tools")
     + ''
         # Copy coreutils, bash, etc.
-        cp ${coreutilsMinimal.out}/bin/* $out/bin
+        cp -d ${coreutilsMinimal.out}/bin/* $out/bin
         (cd $out/bin && rm vdir dir sha*sum pinky factor pathchk runcon shuf who whoami shred users)
 
         cp ${bash.out}/bin/bash $out/bin