Slab only optionally depends on MPI and the Kranc tutorial http://kranccode.org/tutorial.html does use it without MPI (or Carpet for that matter). In 9ea25cd9 this ability was lost due to
MPI_Alltoallv being limited to
int variables for offsets and sizes thus not usable with the 64 bit code anymore.
restores functionality to run without MPI and makes the Kranc tutorial work once more.
It is not really nice since it fudges the function prototype of the
MPI_Alltoallv dummy function used in Slab.