#include <u.h>#include <libc.h> Rune*runestrecpy(Rune *s1, Rune *es1, Rune *s2){	if(s1 >= es1)		return s1; 	while(*s1++ = *s2++){		if(s1 == es1){			s1[-1] = '\0';			break;		}	}	return s1-1;}