When using pax -s to rewrite archived files on the fly, it also rewrites the symlink reference even if these symlinks are relative. This is highly unexpected, not documented and incorrect behavior.
Imagine you the following two files:
bin/test sbin/test -> ../bin/test
If you would archive this using:
find . | pax -d -w -x ustar -s ',^,foo-1.2/,' >foo-1.2.tar
You end up with the following files in the archive:
foo-1.2/bin/test foo-1.2/sbin/test -> foo-1.2/../bin/test