In preparation for the patch that would allow retargeting of locking
routines, rename all lock objects to follow this pattern:
"__<name>_[recursive_]mutex".
Following locks were renamed:
__dd_hash_lock -> __dd_hash_mutex
__sfp_lock -> __sfp_recursive_mutex
__sinit_lock -> __sinit_recursive_mutex
__atexit_lock -> __atexit_recursive_mutex
_arc4random_mutex -> __arc4random_mutex
__env_lock_object -> __env_recursive_mutex
__malloc_lock_object -> __malloc_recursive_mutex
__atexit_mutex -> __at_quick_exit_mutex
__tz_lock_object -> __tz_mutex