Now that sci-libs/brial-1.2.9 can use an external copy of CUDD, we should eventually unbundle the copy that ships with brial. At the moment only the older cudd-2.5.x series is usable from within brial. No rush here, everything still works in the meantime.
Closing for now in light of https://github.com/BRiAl/BRiAl/commit/67a0ce71efe89372418eef74a0984ac97011eda5