(orcc-lib) Make SDL fully optional.
(orcc-lib) Remove the depencencies to sys/stat.h which is not standard: This improve the portability of the library.
(orcc-lib) Clean includes.
(orcc-lib) Move function related to the profiling together.
(orcc-lib) Make threads and roxml optional to improve the portability
(orcc-lib) Replace the structure 'sync_t' by a field in the structure of the mapping agent.
(orcc-lib) Fix ifdef.
(C) Move atexit to the library.