{ stdenv, fetchurl , enableACLs ? true, acl ? null }: assert enableACLs -> acl != null; stdenv.mkDerivation { name = "rsync-3.0.5"; src = fetchurl { url = http://rsync.samba.org/ftp/rsync/src/rsync-3.0.5.tar.gz; sha256 = "1js36yv5s9dic524s7jczqk5myzp67bp24rqhbnikg6lh6pj1b20"; }; buildInputs = stdenv.lib.optional enableACLs acl; meta = { homepage = http://samba.anu.edu.au/rsync/; description = "A fast incremental file transfer utility"; }; }