Provide internal open() function.

This is for the benefit of static versions of Compile and Check functions,
so they do not load anything in advance i.e. custom Magic databases etc ...

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Make Version() static.

Internally it just returns a value from macro set at compile time,
there is no state change nor Magic database needs to be open.

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