sg: revert readlink -f
Created by: keegancsmith
readlink does not support -f on BSD tools. As such this version of the script fails on macOS with
sg installed to /Users/keegan/go/bin/sg
readlink: illegal option -- f
usage: readlink [-n] [file ...]
This reverts commit 925d5703b71a390219b00c9bb4a78521afe22dda. This reverts commit 8e42a279f5d8b47875888ecb11f1bc4da05f8741.