systemd: Get rescue.service and emergency.service to work

pkgs/os-specific/linux/sysvinit/default.nix

@@ -4,12 +4,12 @@ let version = "2.88dsf"; in
 
 stdenv.mkDerivation {
   name = (if withoutInitTools then "sysvtools" else "sysvinit") + "-" + version;
-  
+
   src = fetchurl {
     url = "mirror://savannah/sysvinit/sysvinit-${version}.tar.bz2";
     sha256 = "068mvzaz808a673zigyaqb63xc8bndh2klk16zi5c83rw70wifv0";
   };
-  
+
   prePatch = ''
     # Patch some minimal hard references, so halt/shutdown work
     sed -i -e "s,/sbin/,$out/sbin/," src/halt.c src/init.c src/paths.h
@@ -27,16 +27,17 @@ stdenv.mkDerivation {
     '';
 
   postInstall = stdenv.lib.optionalString withoutInitTools
-    ''  
+    ''
       mv $out/sbin/killall5 $out/bin
       ln -sf killall5 $out/bin/pidof
-      rm -rf $out/sbin
+      shopt -s extglob
+      rm -rf $out/sbin/!(sulogin)
       rm -rf $out/include
       rm -rf $out/share/man/man5
       rm $(for i in $out/share/man/man8/*; do echo $i; done | grep -v 'pidof\|killall5')
       rm $out/bin/{mountpoint,wall} $out/share/man/man1/{mountpoint.1,wall.1}
     '';
-    
+
   meta = {
     homepage = http://www.nongnu.org/sysvinit/;
     description = "Utilities related to booting and shutdown";