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!
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!