Merge bitcoin-core#188: Write PSBTs to file with binary mode

cc3971c GUI: Write PSBTs to file with binary mode (Andrew Chow)

Pull request description:

  As noted in bitcoin/bitcoin#20959, PSBT files should be opened in binary mode as on windows, all newlines are turned into CRLF which produces invalid PSBTs.

  Fixes bitcoin/bitcoin#20959

ACKs for top commit:
  Talkless:
    utACK cc3971c.

Tree-SHA512: fee62b66da844017a44d7d6da6d2d2794b097a7dec33fb07711615df1e94dccc76f987ffcbb325ad1f8db2a2dd6eaf514b6cbd2453e7658b9f6c9fb5c4c41dab

Author: MarcoFalke

src/qt/psbtoperationsdialog.cpp

@@ -145,7 +145,7 @@ void PSBTOperationsDialog::saveTransaction() {
     if (filename.isEmpty()) {
         return;
     }
-    std::ofstream out(filename.toLocal8Bit().data());
+    std::ofstream out(filename.toLocal8Bit().data(), std::ofstream::out | std::ofstream::binary);
     out << ssTx.str();
     out.close();
     showStatus(tr("PSBT saved to disk."), StatusLevel::INFO);

src/qt/sendcoinsdialog.cpp

@@ -434,7 +434,7 @@ void SendCoinsDialog::on_sendButton_clicked()
             if (filename.isEmpty()) {
                 return;
             }
-            std::ofstream out(filename.toLocal8Bit().data());
+            std::ofstream out(filename.toLocal8Bit().data(), std::ofstream::out | std::ofstream::binary);
             out << ssTx.str();
             out.close();
             Q_EMIT message(tr("PSBT saved"), "PSBT saved to disk", CClientUIInterface::MSG_INFORMATION);