Onesided communication seems not to be very stable yet:
-- To be sure that window addresses are long enough the
   parameters 'disp' and 'mlen' MUST be declared as
   Integer(8).
-- A peculiarity of SGI Altix/Origin systems is that
   the buffer 'message(mlen)' must be put in a Common Block
   otherwise 'MPI_Win_Create' will fail without setting all
   kinds of environment variables.
-- As there is no harm in placing 'message(mlen)' in common,
   we retain that for the general version:
   Common /buffer/ message(mlen)
