For a while we had issues with libunwind clashing in R and Julia, and it was a problem for JuliaCall.
There was a PR (libunwind workaround by sbfnk · Pull Request #265 · JuliaInterop/JuliaCall · GitHub) submitted that I just merged, and also did a few other package housekeeping tasks. It would be great if people can try out the master of JuliaCall and see if it works fine, so that we can tag the next release in CRAN.
-viral