ref: ba562a48d3e73476ffaf4b283b4de0b103967f5c
dir: /sys/src/ape/lib/ap/gen/strrchr.c/
#include <string.h>
char*
strrchr(const char *s, int c)
{
char *r;
if(c == 0)
return strchr(s, 0);
r = 0;
while(s = strchr(s, c))
r = (char*)s++;
return r;
}