Fix AddAmmo setting ammo to 99 when trying to add infinite ammo
This affected the portal mission, the crate only gave you 99 portal guns instead of infinite.
// Common/MyInitGuid.h
#ifndef __COMMON_MYINITGUID_H
#define __COMMON_MYINITGUID_H
#ifdef _WIN32
#include <initguid.h>
#else
#define INITGUID
#include "MyGuidDef.h"
DEFINE_GUID(IID_IUnknown,
0x00000000, 0x0000, 0x0000, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46);
#endif
#endif