ref: fbe78d46877a32a8d825d8c93acfdc4466f8ffc3
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;
}