#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;}