New port: math/polymake -- some questions and help needed

Hi ports@

I've been working on a port of polymake (polymake.org). Most of the work 
is done, but there are some questions. Please advise:

- How to deal with machine/installation dependent path names?
polymake installs a helper library into 
${PREFIX}/libexec/polymake/perlx/%%PERL_VERSION%%/amd64-freebsd-thread-multi/auto/Polymake/Ext/Ext.so

amd64-freebsd-thread-multi is the output of

	perl -E 'use Config; print "$Config::Config{archname}\n";'

How do I correctly handle this entry in pkg-plist?

- From reading the Porters Handbook, I get the impression that setting 
DESTDIR is frowned upon. However, if I don't set DESTDIR=${STAGEDIR} in 
the do-install target, "make stage" dumps everything to ${PREFIX}. Any 
comments on this?

- polymake installs a shared library libpolymake.so. I set USE_LDCONFIG, 
but "portlint -A" complains that no libraries are installed. Why?

If I do install the port in its current form, everything looks fine:
$ pkg info polymake
...
Shared Libs provided:
         libpolymake-apps-rt.so.4.4
         libpolymake.so.4.4
...
$

Should I worry about this?

You can find the current state of affairs at philippost.de/polymake.tar.xz

I appreciate any hints and comments you may have. It's my first port and 
I hope I didn't miss anything important. ;-)

Thanks in advance!

Philipp