ref: d25abeac602ebf2c2cb4101b6d51a704d15b6809
dir: /sys/src/libc/port/strchr.c/
#include <u.h>
#include <libc.h>
char*
strchr(char *s, int c)
{
char r;
if(c == 0)
while(*s++)
;
else
while((r = *s++) != c)
if(r == 0)
return 0;
return s-1;
}