Myself and others new to mbed having trouble understanding the various arcane requirements. Adding a mbed_app.json file to enable a library feature instead of using a #define is one of them. Sharing this to help others.

Dependencies:   max32630fthr USBDevice

Revision:
0:60a522ae2e35
Child:
8:d2b660bf5f94
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/USBDevice.lib	Fri Nov 11 21:08:36 2016 +0000
@@ -0,0 +1,1 @@
+https://developer.mbed.org/teams/MaximIntegrated/code/USBDevice/#c5e178adb138