#355 al_show_native_message_box focus on Windows

[Peter Wang]

http://www.allegro.cc/forums/thread/609911/951925#target

We call MessageBoxW to open the message box. When we give the window handle of the display to MessageBoxW, the new window inherits(?) the window proc of the normal Allegro window. For some reason, due to the way the window proc handles the messages, the message box doesn't gain focus when it is created.

[ErwinGame]

Okay