### Please describe the problem.

Installing git annex on MacOS 10.13 HighSierra  via brew install git-annex issues an error:
...
Trap 6

The fix is to install lib magic with this command:

brew install libmagic


### What steps will reproduce the problem?


### What version of git-annex are you using? On what operating system?


### Please provide any additional information below.

[[!format sh """
# If you can, paste a complete transcript of the problem occurring here.
# If the problem is with the git-annex assistant, paste in .git/annex/daemon.log


# End of transcript or log.
"""]]

### Have you had any luck using git-annex before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)

