fix wrong return value from wmemmove on forward copies

[musl] / src / string / strndup.c

#include <stdlib.h>
#include <string.h>

char *strndup(const char *s, size_t n)
{
        size_t l = strnlen(s, n);
        char *d = malloc(l+1);
        if (!d) return NULL;
        memcpy(d, s, l);
        d[l] = 0;
        return d;
}