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

[musl] / src / math / copysign.c

#include "libm.h"

double copysign(double x, double y) {
        union {double f; uint64_t i;} ux={x}, uy={y};
        ux.i &= -1ULL/2;
        ux.i |= uy.i & 1ULL<<63;
        return ux.f;
}