Re-re-revert "chromium: remove preferLocalBuild".

This reverts commit 0696b0ef78.

Okay, now finally, let's get this straight. We actually *want*
preferLocalBuild, *because* we have improved the source splitup in
c92dbffeac.

The idea is to use local builds in order to prevent the source being
pushed to a remote machine, splitted up there (and thus copied again)
and then being copied *again* FROM the remote machine.

"DOH!" - as @edolstra or @rbvermaa would call it... and good d^Hnight.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/applications/networking/browsers/chromium/source/default.nix

@@ -80,6 +80,8 @@ in stdenv.mkDerivation {
       "$main/content/browser/browser_main_loop.cc"
   '';
 
+  preferLocalBuild = true;
+
   passthru = {
     inherit version channel;
     plugins = fetchurl binary;