A basic maxim of GARNOME is "do no harm". The GARNOME build process should only install files into the GARNOME install tree. The build process should never *automatically* install any file into a system directory. That being said, we are left to deal with post-install issues like PAM files. The issue with PAM is that it does not support a search path environment variable like python or pkg-config. Using soft links one way to solve the problem.
You missed his point entirely. The pam files aren't being copied into $GARNOME. So you can create all the dangling symlinks in /etc/pam.d that you like, they won't work...
-- Carson