Note that this bug is in version 1.20.2, but that isn't an option in the version selection box. The configuration help in the menuconfig under [Busybox Settings -> General Configuration -> Support NSA Security Enhanced Linux] has a link to http://www.nsa.gov/selinux/index.html which is an error page. An appropriate link would be http://www.nsa.gov/research/selinux/
Created attachment 4646 [details] The help screen for "Support NSA Security Enhanced Linux" in the menuconfig of 1.20.2
Fixed in git.