Pavan and I chatted on the phone this morning about https://svn.open-mpi.org/trac/hwloc/ticket/4
The *easiest* solution for MPICH2 would be if they could
AC_CONFIG_SUBDIRS our configure script. However, this has the
condition that hwloc's configure could never fail -- e.g., it can't
call AC_MSG_ERROR. For unsupported platforms, it will need to still
succeed and build/install a token libhwloc.la. This libhwloc.a can
just return a graceful failure from hwloc_init() at run-time
indicating that it can't do anything on this platform.
By default, I'm not comfortable with this. But I would be comfortable
with such a scheme if a non-default flag is passed to configure (e.g.,
"--enable-always-build", or perhaps a better name).
Would this be hard to do from the building side? I.e., I have not
looked in the C code much yet -- do we have much code that won't build
on unsupported platforms, or do we need a "generic / always fail" .c
file that is trivial/portable C, but always returns failures for all
hwloc API functions...?