Adjust pkg-config data for include path (#11)
Adjust pkg-config data for include path (#11)

Adjust include path for use libltfs from outside of this project.

User can include it like `#include <libltfs/ltfs.h>`
LinearTapeFileSystem/ltfs,LinearTapeFileSystem/ltfs,LinearTapeFileSystem/ltfs,LinearTapeFileSystem/ltfs,LinearTapeFileSystem/ltfs