ref: fbf9f131b5931defb02ff08d54d1e088d9f51a15
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;
}