Merge remote-tracking branch 'eelco/master' into stdenv-updates

Conflicts:
	pkgs/development/compilers/gcc/4.7/default.nix

Trivial solution.

pkgs/lib/maintainers.nix

@@ -37,6 +37,7 @@
   sander = "Sander van der Burg <s.vanderburg@tudelft.nl>";
   shlevy = "Shea Levy <shea@shealevy.com>";
   simons = "Peter Simons <simons@cryp.to>";
+  smironov = "Sergey Mironov <ierton@gmail.com>";
   thammers = "Tobias Hammerschmidt <jawr@gmx.de>";
   urkud = "Yury G. Kudryashov <urkud+nix@ya.ru>";
   viric = "Lluís Batlle i Rossell <viric@viric.name>";

pkgs/lib/types.nix

@@ -176,6 +176,20 @@ rec {
       fold = op: nul: v: if v == null then nul else elemType.fold op nul v;
     };
 
+    functionTo = elemType: mkOptionType {
+      name = "function that evaluates to a(n) ${elemType.name}";
+      check = lib.traceValIfNot builtins.isFunction;
+      merge = fns:
+        args: elemType.merge (map (fn: fn args) fns);
+      # These are guesses, I don't fully understand iter, fold, delayOnGlobalEval
+      iter = f: path: v:
+        args: elemType.iter f path (v args);
+      fold = op: nul: v:
+        args: elemType.fold op nul (v args);
+      inherit (elemType) delayOnGlobalEval;
+      hasOptions = false;
+    };
+
     # !!! this should be a type constructor that takes the options as
     # an argument.
     optionSet = mkOptionType {