openjdk: Add the 'jre' output.

Note that this is almost completely useless for now, when openjdk is built a separate store path containing only the jre will be built but it will not be added to the environment nor as a gc root. If you want to install just the jre, for now build openjre (which uses the jreOnly parameter). Once multiple outputs are more feature-complete, this should hopefully be useful and remove the need for the jreOnly parameter

svn path=/nixpkgs/trunk/; revision=28481

pkgs/development/compilers/openjdk/default.nix

@@ -50,6 +50,8 @@ stdenv.mkDerivation rec {
     sha256 = "17n0i5cgvfsd6ric70h3n7hr8aqnzd216gaq3603wrxlvggzxbp6";
   };
 
+  outputs = [ "out" ] ++ stdenv.lib.optionals (! jreOnly) [ "jre" ];
+
   buildInputs = [
     unzip
     procps
@@ -114,7 +116,10 @@ stdenv.mkDerivation rec {
   installPhase = ''
     ensureDir $out
     cp -av build/*/j2${if jreOnly then "re" else "sdk"}-image/* $out
-  '';
+  '' + (if jreOnly then "" else ''
+    ensureDir $jre
+    cp -av build/*/j2re-image/* $jre
+  '');
 
   meta = {
     homepage = http://openjdk.java.net/;