fix: handle links on Mac when using `allow` (#696)
fix: handle links on Mac when using `allow` (#696)

At least on macOS, paths passed to `direnv allow <dir>` weren't being
fully resolved during the `allow` process. For example, `direnv allow
/tmp/dir` would store an authorization for /tmp/dir/.envrc. On Macs,
/tmp is an alias for /private/tmp, and when the user actually cd-ed into
/tmp/dir, the path provided by os.Getwd would be /private/tmp/dir.

resolves #694
direnv/direnv,direnv/direnv