ref: a314e313bdd65f8f588cc3188df4b215443c03d7
dir: /lib/c/strncat.c/
#include <string.h>
#undef strncat
char *
strncat(char * restrict dst, const char * restrict src, size_t n)
{
char *ret = dst;
while (*dst)
++dst;
while (n-- > 0 && *src)
*dst++ = *src++;
*dst = '\0';
return ret;
}