acos.s fix: use the formula acos(x) = atan2(sqrt(1-x),sqrt(1+x))

[musl] / src / thread / pthread_barrier_init.c

#include "pthread_impl.h"

int pthread_barrier_init(pthread_barrier_t *b, const pthread_barrierattr_t *a, unsigned count)
{
        if (count-1 > INT_MAX-1) return EINVAL;
        *b = (pthread_barrier_t){ ._b_limit = count-1 | (a?*a:0) };
        return 0;
}