Update notes for submitted changes

* Fix x86/x86_64 getcontext overflow problem.
Update notes for submitted changes

* Adds static lib targets
Update notes for submitted changes

* Removes dependencies on libgcc
Update notes for submitted changes

* Add exception handling unwind code.
Update notes for submitted changes

* Use -Wno-header-guard for clang 3.5
Update notes for submitted changes

* The build system now supports host arch x86_64.
Update notes for submitted changes

* Populate ucontext_t#fpregs_mem when getting the context