https://bugs.gentoo.org/706324
--- a/src/structs.h
+++ b/src/structs.h
@@ -1414,7 +1414,7 @@ struct dictitem_S
 {
     typval_T	di_tv;		// type and value of the variable
     char_u	di_flags;	// flags (only used for variable)
-    char_u	di_key[1];	// key (actually longer!)
+    char_u	di_key[];	// key (actually longer!)
 };
 typedef struct dictitem_S dictitem_T;