Can't be built in module-aware mode

The original discussion can be found in #7 (closed).

The short version is that the Go maintainers are strongly pushing for the adoption of modules, to the point where support for non-module builds is planned to be dropped in the next Go release; at the same time, the Go ecosystem has always implicitly assumed that libraries would follow semver, and Go modules further codify that expectation into the tooling.

libvirt, on the other hand, uses calver instead of semver for the main C library as well as language bindings: as a consequence, libvirt-go can't be built in module-aware mode. This issue can still be worked around with Go 1.16, but as mentioned above with Go 1.17 that is expected to no longer be the case.

Action will need to be taken in order to ensure that libvirt-go keeps working once Go 1.17 has been released.