Define buffer on the stack here.
MPI_Abort can theorically fail.  Add a call to exit() to ensure that the program really stops.
Use xbt_die() for DIE_IMPOSSIBLE.
Check that table[0].name is defined.

Also change "model" for "collective" in find_coll_description().
Be consistent: change buf to an array of int.
Use DBL_MAX for values of type double.
Supernovae builds are deprecated.