Update libadt

[Michael van Acken <mvacken@t-online.de>]

I have updated the libadt distribution to the new "official"
configuration and installation mechanism for oo2c.  To install the
files simply do

  ./configure; make install

and you are set.  As usual the files can be obtained from

  http://home.t-online.de/home/mvacken/

Before you use any of the modules you should check its status in the
file libadt.Mod.  If things are amiss, feal free to fix it and send me
a copy.

Note from the ChangeLog:

    * src/libadt.Mod:
    Added LIBRARY specification.  The version number will stay at 0:0:0
    until the first true release.  To prevent linking of programs against
    this changing library, the Makefile does not create a shared/static
    library by default.

-- mva