An application is an Objective-C program that includes a GUI component,
and by default links in all the GNUstep libraries required for GUI
development, such as the Base and Gui libraries. It accepts all the variables
listed in Common Variables.
— Graphical Applications: APP_NAME
APP_NAME specifies the name of the application to be created. For example if you specify:
APP_NAME = Amber
your application wrapper directory will take the name Amber.app.