#define SYSCALL_RETURN_ERRNO#include"pthread_impl.h"void__lock(volatileint*l){int spins=100000;/* Do not use futexes because we insist that unlocking is a simple * assignment to optimize non-pathological code with no contention. */while(a_xchg(l,1))if(spins) spins--,a_spin();elsesyscall0(__NR_sched_yield);}