Install tests fail if DESTDIR is set

[Jeffrey Hutzelman]

This problem is definintely present in libtool-1.4, but is probably also
present in other versions.  I was building on a RedHat 6.2 system, but
the problem and fix should be platform-independent.

Four tests (demo-inst, mdemo-inst, depdemo-inst, dryrun) attempt to
install into a temporary directory.  They do this by running configure
with the prefix set to the temporary directory.  Unforutnately, this
method does not account for the possiblity that DESTDIR is set when the
tests are run.

If DESTDIR is set during the tests, then files are installed into the
wrong place, if at all.  In my case, DESTDIR happens to be set to an
unwriteable directory during the build (I don't obtain the necessary
privileges to write there until just before running 'make install'), which
causes these tests to fail completely.

For additional details, please check the GNATS database at
http://sources.redhat.com/cgi-bin/gnatsweb.pl and look at automake/225,
which describes a similar problem in automake.

-- Jeffrey T. Hutzelman (N3NHS) <address@hidden>
   Sr. Research Systems Programmer
   School of Computer Science - Research Computing Facility
   Carnegie Mellon University - Pittsburgh, PA