I've got the compiling error with the following codes:
Code:

---

// main.c
#include <acknex.h>
#include <default.c>

var aa;
var bb;
var cc;

void main()
{
   level_load("");
   bb = 10;
   cc = 20;
   aa = max(bb,cc);
}

---

Compiling MAIN.c........
Error in 'MAIN' line 14 : 'max' undeclared identifier
<aa = max(bb,cc);>

Can't compile MAIN.c
Startup failure - any key to abort

Same with aa = min(bb,cc);