add explicit config.h include to export

include/assimp/cexport.h

@@ -48,7 +48,9 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef ASSIMP_BUILD_NO_EXPORT
 
-#include "types.h"
+// Public ASSIMP data structures
+#include <assimp/types.h>
+#include <assimp/config.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -260,4 +262,3 @@ ASSIMP_API void aiReleaseExportBlob( const C_STRUCT aiExportDataBlob* pData );
 
 #endif // ASSIMP_BUILD_NO_EXPORT
 #endif // AI_EXPORT_H_INC
-