A recent bug in libtomcrypt prevented building stoken. See: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=241232
The build log here: http://beefy3.nyi.freebsd.org/data/113amd64-quarterly/517398/logs/errors/stoken-0.92.log
..shows that stoken failed to build for inclusion in pkg repositories, most likely due to this bug (i.e, the dependency pulled in is 1.18.2, not 1.18.2_1 which should include the fix mentioned in #241232)
I suspect fixing the dependency on libtomcrypt to be minimally the version that includes the fix in #241232, would fix the build of stoken.
Possibly this issue only exists on 11.3; I saw that stoken was correctly built for 12.1.