Merge branch 'libusb-1.0' of git://github.com/ttsou/gnuradio-ttsou
This merge fixes libusb build machinery to work for Cygwin, Darwin, Ubuntu,
and F11.
* 'libusb-1.0' of git://github.com/ttsou/gnuradio-ttsou:
usrp: Applied patch from Michael Dickens for Darwin libusb
usrp: Applied patch from Don Ward for Cygwin libusb
fix to restart libusbok checking for non-PKGCONFIG
usrp: Disabled libusb-1.0 debug output by default
merged updated libusb checks with older version
usrp: Enable debug output
usrp: Reorg of libusb error reporting
usrp: Added error checking on hash transfers
augmented search for libusb