Handle cases where libmagic is reasonable up-to-date but doesn't have magic_version() function.

This will be for instance version 5.10 ... 5.13.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Add more support for different versions of libmagic.

See commit fe9d7056112d027c140bf0efd4f43577b102c28e and
b0cc9951f0aef4ac9574b73449bedd339ff73670 for more details.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>