Official FreeBSD 10.3 distribution should link against libutil.so.9, not libutil.so.8
The official distribution of GHC for FreeBSD, as retrieved from  attempts to link against libutil.so.8
FreeBSD 10.3 is actually built against libutil.so.9, and there is no /lib/libutil.so.8 (and no version 8 of the library available via the package manager/ports).
Symlinking /lib/libutil.so.9 to /lib/libutil.so.8 appears to allow GHC to run without issue, but I can't guarantee the results.
Since the distributed GHC tarball is specific to FreeBSD 10.3, it should probably link against libutil.so.9 as well.
(I am completely new to Haskell/GHC and have no clue what "component" to tag this as. I was looking for a 'distribution' or 'packages' component, but can find none. My apologies in advance for tagging it as 'None')