master
move arm-specific translation units out of arch/arm/src, to src/*/arm
further use of _Noreturn, for non-plain-C functions
move __abort_lock to its own file and drop pointless weak_alias trick
remove incorrect fflush from assert failure handler
lift child restrictions after multi-threaded fork
atexit: fail rather than deadlocking after last handler is called
fix compile regression in exit on archs without SYS_pause
remove useless synchronization in exit and quick_exit