This is more than an enhancement, because it adds some pretty basic security features to l2tpd. The enhanced "distribution" of l2tpd is maintained by Jacco de Leeuw, and so is downloaded from his site. The RedHat RPM for l2tpd uses his distribution, so it's been around for awhile. I've tested it as well. The most significant addon is "listen-addr" to the config.
Created attachment 21862 [details] l2tpd-0.69-r1.ebuild
thx, i changed few things and added it as -r1