Use GCC builtin for atomics for guard_acquire
Use GCC builtin for atomics for guard_acquire

open-power/hostboot,alvintpwang/hostboot,csmart/hostboot,alvintpwang/hostboot,csmart/hostboot,alvintpwang/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,alvintpwang/hostboot,csmart/hostboot,Over-enthusiastic/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,open-power/hostboot,alvintpwang/hostboot,Over-enthusiastic/hostboot,open-power/hostboot,csmart/hostboot,Over-enthusiastic/hostboot