Add more support for different versions of libmagic.
Add more support for different versions of libmagic.

See commit fe9d7056112d027c140bf0efd4f43577b102c28e and
b0cc9951f0aef4ac9574b73449bedd339ff73670 for more details.

Signed-off-by: Krzysztof Wilczynski <9bf091559fc98493329f7d619638c79e91ccf029@linux.com>

kwilczynski/go-magic,kwilczynski/go-magic,kwilczynski/go-magic