This variable is not needed since 250f6fdfa341ffcf0534b8adbec436d0bf4e3a57 removed the Kconfig file for the application.
usbus_minimal example
This is a minimalistic example for RIOT's USB stack. The application will initialize and start the USB stack. The stack is started without any USB handlers, it should show up as an empty USB device on the host.
RIOT doesn't own any USB vendor and product ID. To compile this example, add your own vendor and product ID to the makefile:
CFLAGS += -DCONFIG_USB_VID=0xYOURVID -DCONFIG_USB_PID=0xYOURPID
The example demonstrates basic USB communication between a host and a RIOT
based USB peripheral. Tools such as lsusb should display the device and
detailed information about the device such as descriptor strings.