submodule--helper: use C99 named initializer

Start using a named initializer list for SUBMODULE_UPDATE_CLONE_INIT, as
the struct is becoming cumbersome for a typical struct initializer list.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c72931e..ea85838 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -1576,10 +1576,13 @@
 
 	int max_jobs;
 };
-#define SUBMODULE_UPDATE_CLONE_INIT {0, MODULE_LIST_INIT, 0, \
-	SUBMODULE_UPDATE_STRATEGY_INIT, 0, 0, -1, STRING_LIST_INIT_DUP, 0, 0, \
-	NULL, NULL, NULL, \
-	NULL, 0, 0, 0, NULL, 0, 0, 1}
+#define SUBMODULE_UPDATE_CLONE_INIT { \
+	.list = MODULE_LIST_INIT, \
+	.update = SUBMODULE_UPDATE_STRATEGY_INIT, \
+	.recommend_shallow = -1, \
+	.references = STRING_LIST_INIT_DUP, \
+	.max_jobs = 1, \
+}
 
 
 static void next_submodule_warn_missing(struct submodule_update_clone *suc,