I think you missed the point in the title. I installed the libusb-compat package via luci. Among other things, that package should have installed a file called usb.h (somewhere in /usr ) which my project requires at runtime as well as during compilation. I believe it cross compiled because the development machine has its own architecture dependent usb.h. I require a usb.h path on the target, the AR-300M, which will later become a host, used to reprogram microcontrollers in the field.
I am a first time user of this library, so I may have misconceptions, but others have run up against the same roadblock and been unable to proceed for this same reason. Any guidance here could help serve as missing user documentation. I would appreciate any input from someone familiar with the use of the library.