Comment 68 for bug 595650

It's fairly common to have the "legacy" or "stable" branch of a library installed concurrently with its current or development branch. This generally indicates that the interface [is assumed to have] changed between libusb-0.1 and libusb-1.0 such that consumers of the former can't just relink against the latter.

Juggling the version numbers without introducing human error in referencing them is another matter!