Merge branch 'ab/struct-init'

Code cleanup around struct_type_init() functions.

* ab/struct-init:
  string-list.h users: change to use *_{nodup,dup}()
  string-list.[ch]: add a string_list_init_{nodup,dup}()
  dir.[ch]: replace dir_init() with DIR_INIT
  *.c *_init(): define in terms of corresponding *_INIT macro
  *.h: move some *_INIT to designated initializers

config.c

@@ -2073,7 +2073,7 @@ static int configset_add_value(struct config_set *cs, const char *key, const cha
 		e = xmalloc(sizeof(*e));
 		hashmap_entry_init(&e->ent, strhash(key));
 		e->key = xstrdup(key);
-		string_list_init(&e->value_list, 1);
+		string_list_init_dup(&e->value_list);
 		hashmap_add(&cs->config_hash, &e->ent);
 	}
 	si = string_list_append_nodup(&e->value_list, xstrdup_or_null(value));