mxcl/homebrew — pull request #21879 by manphiz (2013-08-13 20:21:21+00:00)
Title: Boost: enforce '--with-mpi' with '--without-single'

* Building MPI support for both single and multi-threaded flavors will
result in duplicated rules for mpi.so. Upstream bug report
https://svn.boost.org/trac/boost/ticket/8841.
* Require '--with-mpi' be used together with '--without-single' until
this is fixed.

Closes #21304.