What exactly are you referring to when you mention X-CURRRENT? Because the only one I'm familiar with is 12-CURRENT, as mentioned
here. You're also hardly giving us enough information to dissect what could have gone wrong.
First I suppose it needs to be mentioned that
FreeBSD CURRENT is an unsupported version, so you're basically on your own for reasons mentioned in that thread. In short: this is a developer snapshot, highly unstable, there are no guarantees that it will even work and the idea is basically to do some bug hunting & fixing yourself.
First thing coming to my mind: are you sure you grabbed the right source tree? I'd probably use something in the likes of
svn co https://svn.freebsd.org/base/head /usr/src12
or perhaps
grab it from Github. You say you installed world and kernel, but the actual process is the other way around, see also
/usr/src/Makefile which explains the process in some good detail as well. Could something have gone wrong there?
Also: why insist on this (unstable) kernel module while there are stable releases available? Such as
radeonkms.ko and/or
i915kms.ko? Are you sure those won't work?