actual configure switch is --with-ntpsnmpd instead of --with-netsnmpd.
Created attachment 240297 [details, diff] ntp-4.2.6_p2.ebuild.patch
Any reason why you didn't commit this yourself? Anyway fixed now in -r1, and removed a bunch of older ebuilds with it.
no problem with asking for maintainers to check the issue to make sure reporter isnt missing anything