ref: a0ba4c1f03a3f99fb17a9edf9b4448db49bb6c46
dir: /sys/src/libc/port/strdup.c/
#include <u.h>
#include <libc.h>
char*
strdup(char *s)
{
char *ns;
ns = malloc(strlen(s) + 1);
if(ns == 0)
return 0;
setmalloctag(ns, getcallerpc(&s));
return strcpy(ns, s);
}