I can't speak for Haskell, but inadequate performance of C FFI in Go is routinely mentioned as the reason why the community is so reluctant to wrap existing C libraries, rather than reimplementing them from scratch in Go.
To be completely honest, I don't know much about C interfaces or systems programming in general. Looking at benchmarks Go's FFI does indeed seem to perform pretty poorly. However, as a web dev, I find it works well for the concurrent programming tasks I find myself dealing with.
