* on i8086-msdos, in the compact and large memory models, set the end of heap to
  be the end of the current program's MCB, instead of 16 bytes earlier

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28442 3ad0048d-3df7-0310-abae-a5850022a9f2