refactor: Split util::insert into its own file

src/Makefile.am

@@ -297,6 +297,7 @@ BITCOIN_CORE_H = \
   util/golombrice.h \
   util/hash_type.h \
   util/hasher.h \
+  util/insert.h \
   util/macros.h \
   util/message.h \
   util/moneystr.h \

src/util/insert.h

@@ -0,0 +1,24 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_UTIL_INSERT_H
+#define BITCOIN_UTIL_INSERT_H
+
+#include <set>
+
+namespace util {
+
+//! Simplification of std insertion
+template <typename Tdst, typename Tsrc>
+inline void insert(Tdst& dst, const Tsrc& src) {
+    dst.insert(dst.begin(), src.begin(), src.end());
+}
+template <typename TsetT, typename Tsrc>
+inline void insert(std::set<TsetT>& dst, const Tsrc& src) {
+    dst.insert(src.begin(), src.end());
+}
+
+} // namespace util
+
+#endif // BITCOIN_UTIL_INSERT_H

src/util/system.h

@@ -38,16 +38,6 @@ int GetNumCores();
 
 namespace util {
 
-//! Simplification of std insertion
-template <typename Tdst, typename Tsrc>
-inline void insert(Tdst& dst, const Tsrc& src) {
-    dst.insert(dst.begin(), src.begin(), src.end());
-}
-template <typename TsetT, typename Tsrc>
-inline void insert(std::set<TsetT>& dst, const Tsrc& src) {
-    dst.insert(src.begin(), src.end());
-}
-
 /**
  * Helper function to access the contained object of a std::any instance.
  * Returns a pointer to the object if passed instance has a value and the type

src/wallet/coinselection.h

@@ -11,8 +11,8 @@
 #include <policy/feerate.h>
 #include <primitives/transaction.h>
 #include <random.h>
-#include <util/system.h>
 #include <util/check.h>
+#include <util/insert.h>
 #include <util/result.h>
 
 #include <optional>