cthread library

Originally developed for the Popcorn Project, cthread is a threading library for Linux. It can be used with glibc as an alternative to pthread. cthread does not use futexes and has similar calling arguments and function names than pthread. E.g. pthread_create is called cthread_create, pthread type is cthread type. cthread is currently work in progress and implements only a subset of the functions implemented in pthread (glibc/nptl). Furthermore cthread has been developed on x86 64bit.