Oh, I did not just copy in libusbx, I compiled and installed it system-wide. Hm, looking at it, the include syntax should probably be in brackets for that case, but my gcc will find headers in /usr/include/libusb-1.0 anyway. However, I guess more relevant here is that it probably did not pick up the compiled libusbx library (which over here is installed in /usr/lib). If your Linux distribution has a development version of libusbx or libusb-1.0, that could be used, too.
I'm heading to my bed now, and I cannot really provide chat support, sorry. Better write to this thread, there might be more helping hands than just mine and others might learn from the questions you had.