 AutoHook.asm shows use of dynamic hooks.
Preserving original MessageBoxA address is needed,
because it will be changed. 2 msg boxes will be displayed,
the 1st is normal, the 2nd is changed by hook.

 AutoHook2.asm shows use of HookApi which works exactly
like dynamic hooks, but with 1 API only.
 HOOK_EXPORT is not used because I hook only selected
modules (here main module).

 Summary:
Using dynamic hooks is more effective than calling HookApi.