Merge recent master into staging

Hydra: ?compare=1148749

Conflicts (easy):
	nixos/modules/virtualisation/containers.nix

lib/maintainers.nix

@@ -68,6 +68,7 @@
   modulistic = "Pablo Costa <modulistic@gmail.com>";
   mornfall = "Petr Ročkai <me@mornfall.net>";
   msackman = "Matthew Sackman <matthew@wellquite.org>";
+  nathan-gs = "Nathan Bijnens <nathan@nathan.gs>";
   notthemessiah = "Brian Cohen <brian.cohen.88@gmail.com>";
   ocharles = "Oliver Charles <ollie@ocharles.org.uk>";
   offline = "Jaka Hudoklin <jakahudoklin@gmail.com>";

lib/types.nix

@@ -200,6 +200,12 @@ rec {
       merge = mergeOneOption;
     };
 
+    either = t1: t2: mkOptionType {
+      name = "${t1.name} or ${t2.name}";
+      check = x: t1.check x || t2.check x;
+      merge = mergeOneOption;
+    };
+
     # Obsolete alternative to configOf.  It takes its option
     # declarations from the ‘options’ attribute of containing option
     # declaration.