text: #include "lib9.h"
  
  char*
  utfrune(char *s, long c)
  {
  	long c1;
  	Rune r;
  	int n;
  
  	if(c < Runesync)		/* not part of utf sequence */
  		return strchr(s, c);
  
  	for(;;) {
  		c1 = *(uchar*)s;
  		if(c1 < Runeself) {	/* one byte rune */
  			if(c1 == 0)
  				return 0;
  			if(c1 == c)
  				return s;
  			s++;
  			continue;
  		}
  		n = chartorune(&r, s);
  		if(r == c)
  			return s;
  		s += n;
  	}
  }
  