Current version has some functions and procedures that allows to change the window title, get the size of the desktop or set a method for the close button. The original Allegro has some other procedures that allows more interaction with the operating system. For example, the win_get_window function returns the window handle identifier on Win32 systems while allegro_icon allows to set the icon for the aplication on Xwindow systems.
Supporting these functions it will be easer to create packages similar than DelphiX or GLScene but using Allegro.