Something with allegro 5.1.11 is causing allegro to crash when calling al_get_joystick(n) where a joystick is not available. It used to simply return NULL if a joystick did not exist, but now in 5.1.11 appears to cause a crash. If the stick is there, everything is fine.

A simple example:

#include <allegro5/allegro.h>

int main(int argc, char *argv[])
{
  al_init();
  al_install_joystick();
  ALLEGRO_JOYSTICK *joy = al_get_joystick(0);
                        // ^ if no joystick is there, program will crash.
  return 0;
}

I'm using Edgar's 5.1.11 binary build (used in speedhack).

Tried this on the allegro-msvc2013-x86-5.1.11 I got from sourceforge, compiling your program under VS 2013. No crashes, it just returned NULL as you'd expect.
On OSX you get an assert fail and an abort, which is inconsistent and maybe needs to be fixed?*

Pete

*Docs say

I dunno, what does Allegro usually do with an out of range value?

My guess is it's regression introduced by the recent stabilization of the Windows joystick code. It used to crash on init if XInput wasn't available (e.g. WinXP)