dns: fix workaround for systems defaulting to ipv6-only sockets

[musl] / src / math / __fpclassify.c

#include <math.h>
#include <stdint.h>

int __fpclassify(double x)
{
        union {double f; uint64_t i;} u = {x};
        int e = u.i>>52 & 0x7ff;
        if (!e) return u.i<<1 ? FP_SUBNORMAL : FP_ZERO;
        if (e==0x7ff) return u.i<<12 ? FP_NAN : FP_INFINITE;
        return FP_NORMAL;
}