polkit, pulseaudio: Drop some Linux-specific dependencies

pkgs/desktops/gnome-2/platform/libgnome/default.nix

@@ -3,7 +3,7 @@
 
 stdenv.mkDerivation rec {
   name = src.pkgname;
-  
+
   src = fetchurl_gnome {
     project = "libgnome";
     major = "2"; minor = "32"; patchlevel = "1";

pkgs/development/libraries/polkit/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchurl, pkgconfig, glib, expat, pam, intltool, gettext
 , gobjectIntrospection
-, useSystemd ? true, systemd }:
+, useSystemd ? stdenv.isLinux, systemd }:
 
 let
 

pkgs/servers/pulseaudio/default.nix

@@ -17,7 +17,7 @@ stdenv.mkDerivation rec {
 
   # Since `libpulse*.la' contain `-lgdbm' and `-lcap', it must be propagated.
   propagatedBuildInputs
-    = [ gdbm ] ++ stdenv.lib.optionals (!stdenv.isDarwin) [ libcap ];
+    = [ gdbm ] ++ stdenv.lib.optionals stdenv.isLinux [ libcap ];
 
   buildInputs =
     [ pkgconfig gnum4 libtool intltool glib dbus avahi libsamplerate libsndfile
@@ -25,7 +25,7 @@ stdenv.mkDerivation rec {
     ++ stdenv.lib.optional jackaudioSupport jackaudio
     ++ stdenv.lib.optionals x11Support [ xlibs.xlibs xlibs.libXtst xlibs.libXi ]
     ++ stdenv.lib.optional useSystemd systemd
-    ++ stdenv.lib.optionals (!stdenv.isDarwin) [ alsaLib bluez sbc udev ];
+    ++ stdenv.lib.optionals stdenv.isLinux [ alsaLib bluez sbc udev ];
 
   preConfigure = ''
     # Move the udev rules under $(prefix).