Fixed variable names to be consistent across functions

src/joystick/windows/SDL_windowsjoystick.c

@@ -400,8 +400,9 @@ static const char *
 WINDOWS_JoystickGetDeviceName(int device_index)
 {
     JoyStick_DeviceData *device = SYS_Joystick;
+    int index;
 
-    for (; device_index > 0; device_index--)
+    for (index = device_index; index > 0; index--)
         device = device->pNext;
 
     return device->joystickname;
@@ -458,25 +459,26 @@ WINDOWS_JoystickGetDeviceInstanceID(int device_index)
 static int
 WINDOWS_JoystickOpen(SDL_Joystick * joystick, int device_index)
 {
-    JoyStick_DeviceData *joystickdevice = SYS_Joystick;
+    JoyStick_DeviceData *device = SYS_Joystick;
+    int index;
 
-    for (; device_index > 0; device_index--)
-        joystickdevice = joystickdevice->pNext;
+    for (index = device_index; index > 0; index--)
+        device = device->pNext;
 
     /* allocate memory for system specific hardware data */
-    joystick->instance_id = joystickdevice->nInstanceID;
+    joystick->instance_id = device->nInstanceID;
     joystick->hwdata =
         (struct joystick_hwdata *) SDL_malloc(sizeof(struct joystick_hwdata));
     if (joystick->hwdata == NULL) {
         return SDL_OutOfMemory();
     }
     SDL_zerop(joystick->hwdata);
-    joystick->hwdata->guid = joystickdevice->guid;
+    joystick->hwdata->guid = device->guid;
 
-    if (joystickdevice->bXInputDevice) {
-        return SDL_XINPUT_JoystickOpen(joystick, joystickdevice);
+    if (device->bXInputDevice) {
+        return SDL_XINPUT_JoystickOpen(joystick, device);
     } else {
-        return SDL_DINPUT_JoystickOpen(joystick, joystickdevice);
+        return SDL_DINPUT_JoystickOpen(joystick, device);
     }
 }