cups: split the $lib output

This saves > 10 MB from most closures.
Printing test succeeds on x86_64-linux.

pkgs/misc/cups/default.nix

@@ -18,8 +18,7 @@ stdenv.mkDerivation rec {
     sha256 = "1xp4ji4rz3xffsz6w6nd60ajxvvihn02pkyp2l4smhqxbmyvp2gm";
   };
 
-  # FIXME: the cups libraries contains some $out/share strings so can't be split.
-  outputs = [ "out" "dev" "man" ]; # TODO: above
+  outputs = [ "out" "lib" "dev" "man" ];
 
   buildInputs = [ pkgconfig zlib libjpeg libpng libtiff libusb gnutls libpaper ]
     ++ optionals stdenv.isLinux [ avahi pam dbus systemd acl ]
@@ -30,6 +29,13 @@ stdenv.mkDerivation rec {
   propagatedBuildInputs = [ gmp ];
 
   configureFlags = [
+    # Put just lib/* and locale into $lib; this didn't work directly.
+    # lib/cups is moved back to $out in postInstall.
+    # Beware: some parts of cups probably don't fully respect these.
+    "--prefix=$(lib)"
+    "--datadir=$(out)/share"
+    "--localedir=$(lib)/share/locale"
+
     "--localstatedir=/var"
     "--sysconfdir=/etc"
     "--with-systemd=\${out}/lib/systemd/system"
@@ -68,6 +74,8 @@ stdenv.mkDerivation rec {
   enableParallelBuilding = true;
 
   postInstall = ''
+      moveToOutput lib/cups "$out"
+
       # Delete obsolete stuff that conflicts with cups-filters.
       rm -rf $out/share/cups/banners $out/share/cups/data/testprint
 

pkgs/misc/cups/drivers/samsung/4.00.39/default.nix

@@ -16,7 +16,7 @@
 # Do not bump lightly! Visit <http://www.bchemnet.com/suldr/supported.html>
 # to see what will break when upgrading. Consider a new versioned attribute.
 let
-  cups' = cups.out;
+  cups' = stdenv.lib.getLib cups;
 in stdenv.mkDerivation rec {
   name = "samsung-UnifiedLinuxDriver-${version}";
   version = "4.00.39";

pkgs/misc/cups/drivers/samsung/default.nix

@@ -72,10 +72,10 @@ in stdenv.mkDerivation rec {
 
   for bin in $out/bin/*; do
     patchelf --set-interpreter "$(cat $NIX_CC/nix-support/dynamic-linker)" "$bin"
-    patchelf --set-rpath "$out/lib:${cups.out}/lib" "$bin"
+    patchelf --set-rpath "$out/lib:${stdenv.lib.getLib cups}/lib" "$bin"
   done
 
-  patchelf --set-rpath "$out/lib:${cups.out}/lib" "$out/lib/libscmssc.so"
+  patchelf --set-rpath "$out/lib:${stdenv.lib.getLib cups}/lib" "$out/lib/libscmssc.so"
 
   ln -s ${stdenv.cc.cc.lib}/lib/libstdc++.so.6 $out/lib/