An update. There is a pull request on juliadep at github for a new brew formula that fixes the problem. Unfortunately, staticfloat hasn't started creating bottles (binaries) for el capitan so no immediate solution.
However, the new formula is available as a commit. Anyway I can get Homebrew.jl to use a specific commit from github. Pkg.clone() doesn't seem to do it and there appears to be no way to get Homebrew to do it. Guess I'll have to wait.
