I think I have the first part of the embedding code done -- it builds and compiles hwloc just like today's build system does (but a bunch of the m4 behind the scenes has moved around quite a bit to enable the embedding stuff). :-)
Could you guys try builds on the supported platforms to see if I broke anything? I only have access to rhel4, rhel5, and osx. The code is in a mercurial branch here:
I'm working on the actual embedding stuff now, but wanted to ensure that I at least got the first parts right.