patch 7.4.2090

Problem:    Using submatch() in a lambda passed to substitute() is verbose.
Solution:   Use a static list and pass it as an optional argument to the
            function.  Fix memory leak.

src/structs.h

@@ -1244,6 +1244,14 @@ struct listvar_S
     list_T	*lv_used_prev;	/* previous list in used lists list */
 };
 
+/*
+ * Static list with 10 items.  Use init_static_list() to initialize.
+ */
+typedef struct {
+    list_T	sl_list;	/* must be first */
+    listitem_T	sl_items[10];
+} staticList10_T;
+
 /*
  * Structure to hold an item of a Dictionary.
  * Also used for a variable.