#include <u.h>#include <libc.h>  /* * Return pointer to first occurrence of s2 in s1, * 0 if none */char*utfutf(char *s1, char *s2){	char *p;	long f, n1, n2;	Rune r; 	n1 = chartorune(&r, s2);	f = r;	if(f <= Runesync)		/* represents self */		return strstr(s1, s2); 	n2 = strlen(s2);	for(p=s1; (p=utfrune(p, f)); p+=n1)		if(strncmp(p, s2, n2) == 0)			return p;	return 0;}