How about the following changes to the way emacs finds the pdmp file:

The existing algorithm remains unchanged as far as how the pdmp files
are named and the order in which they are looked up.  But when emacs
tries to guess the pdmp location, it does not fail if it finds a bad
pdmp signature but it continues searching.  (This would accomodate
having multiple variants of the same emacs installed on the system:
eg. /usr/bin/emacs-nox, /usr/bin/emacs-motif, /usr/bin/emacs-athena ...)

Then on GNU/Linux if the pdmp is still not loaded, emacs can try to
find the real argv[0] by looking at /proc/self/exe and retry the
search effort.  This would take care of the case where, say,
~/bin/emacs is a symlink to /build/emacs/src/emacs.

The idea is illustrated in the patch.  Maybe an improved version could
be added to emacs ---Madhu