symlink problems with mac os

[Per Bothner]

On 10/22/2017 05:00 AM, Björn Raupach wrote:
> The readlink version of macOS isn’t the same as GNU/Linux one. The latter version does follow symlinks with -f. The macOS one does not support this feature.
> 
> I stumbled upon this while working on a port for MacPorts<https://www.macports.org>  Should make kawa easier to install and upgrade on macOS. (Of course it is already simple enough being a jar file and such…)

There is a Homebrew port fof Kawa which avoids the problem by patching
bin/kawa before installing it:

https://github.com/Homebrew/homebrew-core/blob/master/Formula/kawa.rb

Another option is to install GNU readlink.

I considered replacing readlink -f by realpath, but as Mac OS doesn't
have readlink either, I don't see how that would help.

We could make the script more complicated, so it can work with plain readlink,
perhaps based on https://github.com/mkropat/sh-realpath/blob/master/realpath.sh .
I'm not thrilled to complicate the script that much, but it may be better
than adding a dependency.

The reason for the readlink to handle the case that you install kawa
as a symlink for example /usr/local/bin/kawa -> /opt/kawa-3.0/bin/kawa .
I think that is useful to support - and it doesn't work without the -f.
-- 
	--Per Bothner
per@bothner.com   http://per.bothner.com/