GetMem procedure

  DECLARATION:  GetMem(var P : pointer; Size : word);

      PURPOSE:  Creates a new dynamic variable of a specified size

         UNIT:  System

      REMARKS:  Creates a new dynamic variable of a specified size, and stores
                the address of the block in the specified pointer variable.
                P is a pointer variable of any pointer type.  Size is an
                expression of word-type which specifies the size in bytes of
                the new variable to allocate.  This new variable can then be
                referenced as P^.

                NOTE:  If there is not enough memory available on the heap a
                       runtime error will occur.  See the HeapError function.

  DIFFERENCES:  in v3.0, Size was an integer.