make installcheck

[Martin Grabmueller]

Okay, I have just committed the `make installcheck' version of the
example checking stuff.  I have tested it with `make distcheck', `make
install && make installcheck' and with `$(top_srcdir) !=
$(top_builddir)'.

I really hope it does work now and doesn't break the snapshots
anymore.  Please test.

I think the `make installcheck' solution is cleaner and makes sure we
find broken examples by doing a `make distcheck', which should be done
occasionaly anyway.

Best regards,
  'martin