make sure to include function declarations from calldata.h

libobs/obs-source.c

@@ -17,6 +17,7 @@
 
 #include "media-io/format-conversion.h"
 #include "util/platform.h"
+#include "callback/calldata.h"
 #include "graphics/matrix3.h"
 #include "graphics/vec3.h"
 

libobs/obs.c

@@ -15,6 +15,8 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ******************************************************************************/
 
+#include "callback/calldata.h"
+
 #include "obs.h"
 #include "obs-data.h"
 #include "obs-module.h"