* Several buildInputs of Gnome-related packages should be

propagatedBuildInputs, because those inputs are required by the *.pc
  or *.la files of the package:

  - If a *.pc file references a non-propagated input, then Gnome
    packages have the bad tendency to silently ignore this problem in
    configure scripts - the failure of a command like `pkg-config
    --cflags foo' will be ignored if a dependency of foo.pc is
    missing, so no flags will be added, and the build will fail later
    on a missing header or library.

  - If a *.la file references a non-propagated input, the build will
    also fail, because Libtool will add library dependencies that it
    cannot find.  (Arguably *.la files should never reference packages
    that aren't in the corresponding *.pc file, but they do it
    anyway).

  By setting the propagatedBuildInputs properly, it should be possible
  to get rid of all the NIX_CFLAGS_COMPILE / NIX_LDFLAGS hacks in the
  Gnome expressions.

svn path=/nixpkgs/branches/xorg-7.5/; revision=18084

pkgs/development/libraries/policykit/default.nix

@@ -10,9 +10,9 @@ stdenv.mkDerivation rec {
   };
   
   buildInputs =
-    [ pkgconfig glib dbus.libs dbus_glib expat pam intltool
-      gettext libxslt
-    ];
+    [ pkgconfig glib dbus_glib pam intltool gettext libxslt ];
+
+  propagatedBuildInputs = [ expat dbus.libs ];
 
   configureFlags = "--localstatedir=/var --sysconfdir=/etc";