Folks, currently, mpich (master and previous releases) cannot be built on OpenBSD 5.7 and later. the root cause is 'struct statfs' has no f_type field. here is attached a patch that fixes that, and add some extra #ifdef protections this issue was initially reported at https://www.open-mpi.org/community/lists/devel/2015/05/17449.php and more recently at https://github.com/open-mpi/ompi/issues/1635 Cheers, Gilles