Merge remote-tracking branch 'origin/mac_fixes'
Merge branch 'master' into coroutine-ppc
Temporarily work around compilation error

in hpx/util/coroutine/detail/self.hpp undecorate_self is defined - but only if GENERIC_COROUTINES are off.
When they are on, the definitions is skipped. However, runtime/components/server/locking_hook.hpp
uses it whether or not GENERIC_COROUTINES are on/off.
Fix another compilation problem caused by GENERIC_COROUTINES cleanup

I'm not sure when the code controlled by this #ifdedf should be used
but this fixes compilation for me currently.
Partially implement a stack rebind function for posix context

This is not yet tested and it may be necessary to recreate the context
rather than just resetting the stack pointer on an existing one.
@todo : check trampoline return address etc