Merge branch 'osx' of git://github.com/seanogden/po6

* 'osx' of git://github.com/seanogden/po6:
  add osx support
Merge barrier and barrier_portable
Bump to 0.4.dev
Switch from gtest to th.
Change contact point to robert@hyperdex
Remove useless "config.h"
Add MAKEFLAGS
Update WANAL
po6::pathname::realpath
Update gitignore
Update th.
Remove unused strerror_r file
Update th to 604660bfda3d4e330a7452c898970aef27403fd1
Update wanal and th
Add .tarballignore
Add upack file
Update upack file.
Update libpo6
Make "source" universal
Full OS X compatibility.