diff --git a/src/mux/muxi.h b/src/mux/muxi.h
index c1c86d3a..5006fc99 100644
--- a/src/mux/muxi.h
+++ b/src/mux/muxi.h
@@ -103,7 +103,7 @@ typedef struct {
   uint32_t      chunkSize;
 } ChunkInfo;
 
-const ChunkInfo kChunks[LIST_ID + 1];
+extern const ChunkInfo kChunks[LIST_ID + 1];
 
 //------------------------------------------------------------------------------
 // Helper functions.