glibc/hurd: Make Mach & Hurd headers propagated build inputs.

svn path=/nixpkgs/trunk/; revision=21906

pkgs/development/libraries/glibc-2.11/default.nix

@@ -39,9 +39,18 @@ in
   //
 
   (if hurdHeaders != null
-   then {
+   then rec {
      inherit machHeaders hurdHeaders mig fetchgit;
 
+     propagatedBuildInputs = [ machHeaders hurdHeaders ];
+
+     passthru = {
+       # When building GCC itself `propagatedBuildInputs' above is not
+       # honored, so we pass it here so that the GCC builder can do the right
+       # thing.
+       inherit propagatedBuildInputs;
+     };
+
      # XXX: Remove this hack in `stdenv-updates'.
      builder = ./builder2.sh;
    }