absolute install dir paths for Fortran includes?

[MLH]

I have autoconf'ed a suite of old Fortran programs. I use a Fortran
include template to pull in variables determined by autoconf at
configure time. However, I believe I need to determine the *absolute
paths* to install directories in this Fortran include file and
can't reliably determine how to do this - especially when they
don't exist at configure time.

Suggestions welcome,

Thanks