ref: 7e2a5f4157fe70b29190781bc7b81f923d6de9b6
dir: /sys/src/libc/port/runestrncat.c/
#include <u.h>
#include <libc.h>
Rune*
runestrncat(Rune *s1, Rune *s2, long n)
{
Rune *os1;
os1 = s1;
s1 = runestrchr(s1, 0);
while(*s1++ = *s2++)
if(--n < 0) {
s1[-1] = 0;
break;
}
return os1;
}