#include <u.h>#include <libc.h> /* * Return pointer to first occurrence of s2 in s1, * 0 if none */Rune*runestrstr(Rune *s1, Rune *s2){	Rune *p, *pa, *pb;	int c0, c; 	c0 = *s2;	if(c0 == 0)		return s1;	s2++;	for(p=runestrchr(s1, c0); p; p=runestrchr(p+1, c0)) {		pa = p;		for(pb=s2;; pb++) {			c = *pb;			if(c == 0)				return p;			if(c != *++pa)				break;		}	}	return 0;}