udev: complete rework

- systemd puts all into one output now (except for man),
  because I wasn't able to fix all systemd/udev refernces
  for NixOS to work well
- libudev is now by default *copied* into another path,
  which is what most packages will use as build input :-)
- pkgs.udev = [ libudev.out libudev.dev ]; because there are too many
  references that just put `udev` into build inputs (to rewrite them all),
  also this made "${udev}/foo" fail at *evaluation* time
  so it's easier to catch and change to something more specific

pkgs/development/libraries/mesa/default.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchurl, fetchpatch, pkgconfig, intltool, autoreconfHook, substituteAll
-, file, expat, libdrm, xorg, wayland, udev, llvmPackages, libffi, libomxil-bellagio
+, file, expat, libdrm, xorg, wayland, libudev, llvmPackages, libffi, libomxil-bellagio
 , libvdpau, libelf, libva
 , grsecEnabled
 , enableTextureFloats ? false # Texture floats are patented, see docs/patents.txt
@@ -48,7 +48,7 @@ stdenv.mkDerivation {
   ] ++ optional stdenv.isLinux
       (substituteAll {
         src = ./dlopen-absolute-paths.diff;
-        inherit (udev) libudev;
+        libudev = libudev.out;
       });
 
   postPatch = ''
@@ -107,7 +107,7 @@ stdenv.mkDerivation {
     glproto dri2proto dri3proto presentproto
     libX11 libXext libxcb libXt libXfixes libxshmfence
     libffi wayland libvdpau libelf libXvMC /* libomxil-bellagio libva */
-  ] ++ optional stdenv.isLinux udev;
+  ] ++ optional stdenv.isLinux libudev;
 
   enableParallelBuilding = true;
   doCheck = false;