reftable/merged: make merged_iter structure private

The `merged_iter` structure is not used anywhere outside of "merged.c",
but is declared in its header. Move it into the code file so that it is
clear that its implementation details are never exposed to anything.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

reftable/merged.c

@@ -17,6 +17,15 @@ license that can be found in the LICENSE file or at
 #include "reftable-error.h"
 #include "system.h"
 
+struct merged_iter {
+	struct reftable_iterator *stack;
+	uint32_t hash_id;
+	size_t stack_len;
+	uint8_t typ;
+	int suppress_deletions;
+	struct merged_iter_pqueue pq;
+};
+
 static int merged_iter_init(struct merged_iter *mi)
 {
 	for (size_t i = 0; i < mi->stack_len; i++) {

reftable/merged.h

@@ -9,7 +9,7 @@ license that can be found in the LICENSE file or at
 #ifndef MERGED_H
 #define MERGED_H
 
-#include "pq.h"
+#include "system.h"
 
 struct reftable_merged_table {
 	struct reftable_table *stack;
@@ -24,15 +24,6 @@ struct reftable_merged_table {
 	uint64_t max;
 };
 
-struct merged_iter {
-	struct reftable_iterator *stack;
-	uint32_t hash_id;
-	size_t stack_len;
-	uint8_t typ;
-	int suppress_deletions;
-	struct merged_iter_pqueue pq;
-};
-
 void merged_table_release(struct reftable_merged_table *mt);
 
 #endif