I tried using luadch as the precompiled Debian build and also as compiled from source. With both ways luasec doesn't work. In the end I resolved this by installing the lua-sec packages and symlink the files to the luadch directory.
$ ls -l luadch/lib/luasec/*
luadch/lib/luasec/lua:
total 0
lrwxrwxrwx 1 dcpp dcpp 34 Mar 3 08:55 options.lua -> /usr/share/lua/5.2/ssl/options.lua
lrwxrwxrwx 1 dcpp dcpp 26 Mar 3 08:55 ssl.lua -> /usr/share/lua/5.2/ssl.lua
luadch/lib/luasec/ssl:
total 0
lrwxrwxrwx 1 dcpp dcpp 40 Mar 3 08:55 ssl.so -> /usr/lib/x86_64-linux-gnu/lua/5.1/ssl.so