drbd was installing files into $out/nix/store/... due to the usage of DESTDIR
(setting both DESTDIR + prefix to $out will cause files to be installed into $out/$out/...)
- 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
drbdsetup. Otherwise "drbdadm primary --force" won't work as
expected (the kernel will say "State change failed: Need access to
UpToDate data").
svn path=/nixpkgs/trunk/; revision=30195
