How can I get the behavior of GNU’s readlink -f on a Mac? [closed]

On Linux, the readlink utility accepts an option -f that follows additional links. This doesn’t seem to work on Mac and possibly BSD based systems. What would the equivalent be?

Here’s some debug information:

$ which readlink; readlink -f
/usr/bin/readlink
readlink: illegal option -f
usage: readlink [-n] [file ...]