{stdenv, fetchurl, libcap}: assert stdenv.isLinux -> libcap != null; stdenv.mkDerivation { name = "ntp-4.2.2p4"; src = fetchurl { url = http://www.eecis.udel.edu/~ntp/ntp_spool/ntp4/ntp-4.2.2p4.tar.gz; md5 = "916fe57525f8327f340b203f129088fa"; }; configureFlags = " --without-crypto ${if stdenv.isLinux then "--enable-linuxcaps" else ""} "; buildInputs = if stdenv.isLinux then [libcap] else []; }