ref: 2cb45ba7f64f83e48609b47218c8fb70cbaced5b
dir: /sys/src/libc/port/strrchr.c/
#include <u.h>
#include <libc.h>
char*
strrchr(char *s, int c)
{
	char *r;
	if(c == 0)
		return strchr(s, 0);
	r = 0;
	while(s = strchr(s, c))
		r = s++;
	return r;
}