guile-2-test: Attempt to provide Hydra with what it wants.

Thanks to Michael Raskin!

svn path=/nixpkgs/trunk/; revision=17280

pkgs/top-level/guile-2-test.nix

@@ -12,9 +12,30 @@ let
     };
   };
 
+  /* Perform a job on the given set of platforms.  The function `f' is
+     called by Hydra for each platform, and should return some job
+     to build on that platform.  `f' is passed the Nixpkgs collection
+     for the platform in question. */
+  testOn = systems: f: {system ? builtins.currentSystem}:
+    if pkgs.lib.elem system systems
+    then f (allPackages {inherit system;})
+    else {};
+
+  /* Map an attribute of the form `foo = [platforms...]'  to `testOn
+     [platforms...] (pkgs: pkgs.foo)'. */
+  mapTestOn = pkgs.lib.mapAttrsRecursiveCond
+    (as: !(as ? type && as.type == "job"))
+    (path: value:
+      let
+        job = toJob value;
+        getPkg = pkgs:
+          pkgs.lib.addMetaAttrs { schedulingPriority = toString job.schedulingPriority; }
+          (pkgs.lib.getAttrFromPath path pkgs);
+      in testOn job.systems getPkg);
+
   inherit (pkgs.lib.platforms) linux darwin cygwin allBut all;
 
-in {
+in (mapTestOn {
   /* The package list below was obtained with:
 
      cat top-level/all-packages.nix				\
@@ -43,4 +64,4 @@ in {
   ballAndPaddle = linux;
   drgeo = linux;
   lilypond = linux;
-}
+})