diff --git a/av1/encoder/ethread.h b/av1/encoder/ethread.h
index a2323ff..36bf5e1 100644
--- a/av1/encoder/ethread.h
+++ b/av1/encoder/ethread.h
@@ -18,6 +18,7 @@
 
 struct AV1_COMP;
 struct ThreadData;
+struct AV1RowMTSyncData;
 
 typedef struct EncWorkerData {
   struct AV1_COMP *cpi;
@@ -25,6 +26,11 @@
   int start;
 } EncWorkerData;
 
+void av1_row_mt_sync_read_dummy(struct AV1RowMTSyncData *const row_mt_sync,
+                                int r, int c);
+void av1_row_mt_sync_write_dummy(struct AV1RowMTSyncData *const row_mt_sync,
+                                 int r, int c, const int cols);
+
 void av1_encode_tiles_mt(struct AV1_COMP *cpi);
 void av1_encode_tiles_row_mt(struct AV1_COMP *cpi);