sysklogd: Support systemd socket-based activation

Syslogd cannot open /dev/log directly but must receive syslog messages
from systemd (http://www.freedesktop.org/wiki/Software/systemd/syslog).
The patch adds support for that.

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

@@ -2,9 +2,24 @@
 
 stdenv.mkDerivation {
   name = "sysklogd-1.5";
-  builder = ./builder.sh;
+
   src = fetchurl {
     url = http://www.infodrom.org/projects/sysklogd/download/sysklogd-1.5.tar.gz;
     sha256 = "0wxpkrznqwz4dy11k90s2sqszwp7d4mlc0ag8288wa193plvhsb1";
   };
+
+  patches = [ ./systemd.patch ];
+
+  installFlags = "BINDIR=$(out)/sbin MANDIR=$(out)/share/man INSTALL=install";
+
+  preConfigure =
+    ''
+      sed -e 's@-o \''${MAN_USER} -g \''${MAN_GROUP} -m \''${MAN_PERMS} @@' -i Makefile
+    '';
+
+  preInstall = "mkdir -p $out/share/man/man5/ $out/share/man/man8/ $out/sbin";
+
+  meta = {
+    description = "A system logging daemon";
+  };
 }