ATOMIC_DEC          9 ruby_atomic.h  # define ATOMIC_DEC(var) __atomic_fetch_sub(&(var), 1, __ATOMIC_SEQ_CST)
ATOMIC_DEC         30 ruby_atomic.h  # define ATOMIC_DEC(var) __sync_fetch_and_sub(&(var), 1)
ATOMIC_DEC         48 ruby_atomic.h  # define ATOMIC_DEC(var) InterlockedDecrement(&(var))
ATOMIC_DEC         99 ruby_atomic.h  # define ATOMIC_DEC(var) atomic_dec_uint(&(var))
ATOMIC_DEC        129 ruby_atomic.h  # define ATOMIC_DEC(var) ((var)--)