adb: get libusb compiling on Windows.

This still doesn't work yet because libusb doesn't support hotplug on
Windows yet, but it's in the milestones for the next libusb release,
and this is enough to start poking around with the WinUSB device-side
stuff, so leave it broken for now.

Bug: http://b/68993980
Test: set ADB_LIBUSB=1; adb.exe server nodaemon aborts in the expected place
Change-Id: Icef7d46e31c847d6a8e724c6f58ae5db43673c16