Merge #18134: Replace std::to_string with locale-independent alternative

d056df033a Replace std::to_string with locale-independent alternative (Ben Woosley)

Pull request description:

  Addresses #17866 following practicalswift's suggestion:
  https://github.com/bitcoin/bitcoin/issues/17866#issuecomment-584287299

  ~Used ::ToString to avoid aliasing issues. Left uses in QT and test.~

ACKs for top commit:
  practicalswift:
    ACK d056df033a
  laanwj:
    ACK d056df033a

Tree-SHA512: 9e6966a9cdd14f4a1a40d9f0fa7c402aed22b2f1ad8681708e22b050d51a91c5d62220a9ec4c425be2d57acf5c964fca87a5e981b5cbff048bc3b6720dae92b7

src/qt/optionsmodel.cpp

@@ -17,6 +17,7 @@
 #include <net.h>
 #include <netbase.h>
 #include <txdb.h> // for -dbcache defaults
+#include <util/string.h>
 
 #include <QDebug>
 #include <QSettings>
@@ -241,7 +242,7 @@ void OptionsModel::SetPruneEnabled(bool prune, bool force)
     QSettings settings;
     settings.setValue("bPrune", prune);
     const int64_t prune_target_mib = PruneGBtoMiB(settings.value("nPruneSize").toInt());
-    std::string prune_val = prune ? std::to_string(prune_target_mib) : "0";
+    std::string prune_val = prune ? ToString(prune_target_mib) : "0";
     if (force) {
         m_node.forceSetArg("-prune", prune_val);
         return;