The unix wrapper script can be simplified, in particular, sed is not required here.
What is the benefit of changing this?
sh, sed, grep, awk and vi among others are very basic tools you can expect to find on any unix system.
readlink is not available on HP-UX. On other systems syntax may not be compatible.
For example on MacOSX http://stackoverflow.com/questions/1055671/how-can-i-get-the-behavior-of-gnus-readlink-f-on-a-mac
This is also true for other BSD variants.
I wasn't aware of this, sorry. I guess this issue should be closed then.