Assbin: add unittest.

code/AssbinExporter.h

@@ -46,6 +46,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef AI_ASSBINEXPORTER_H_INC
 #define AI_ASSBINEXPORTER_H_INC
 
-// nothing really needed here - reserved for future use like properties
+#include <assimp/defs.h>
 
-#endif
+// nothing really needed here - reserved for future use like properties
+namespace Assimp {
+
+void ASSIMP_API ExportSceneAssbin(const char* pFile, IOSystem* pIOSystem, const aiScene* pScene, const ExportProperties* /*pProperties*/);
+
+}
+
+#endif // AI_ASSBINEXPORTER_H_INC