fix shared linking against libtorrent_test

test/settings.cpp

@@ -32,6 +32,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/settings_pack.hpp"
 #include "libtorrent/alert.hpp"
+#include "settings.hpp"
 
 using namespace libtorrent;
 

test/settings.hpp

@@ -31,6 +31,7 @@ POSSIBILITY OF SUCH DAMAGE.
 */
 
 #include "libtorrent/settings_pack.hpp"
+#include "test.hpp"
 
-libtorrent::settings_pack settings();
+libtorrent::settings_pack EXPORT settings();