diff --git a/src/odb_mempack.c b/src/odb_mempack.c
index 594a2784c..68db3bc32 100644
--- a/src/odb_mempack.c
+++ b/src/odb_mempack.c
@@ -24,7 +24,7 @@ struct memobject {
 	git_oid oid;
 	size_t len;
 	git_otype type;
-	char data[];
+	char data[GIT_FLEX_ARRAY];
 };
 
 struct memory_packer_db {