ref: ca159744ce0e57a00d89f49dcd3617a1ef7e4761
dir: /src/libc/string/strncat.c/
#include <string.h>
#undef strncat
char *
strncat(char *restrict s1, const char *restrict s2, size_t n)
{
char *ret = s1;
while(*s1)
++s1;
while (n-- > 0 && *s2)
*s1++ = *s2++;
*s1 = '\0';
return ret;
}