Merge #13055: qt: Don't log to console by default

aee80b0ef9 qt: Don't log to console by default (Wladimir J. van der Laan)

Pull request description:

  Default `-printtoconsole` to false for the GUI. GUI programs should not print to the console unnecessarily. For example, when launched by the window manager, the output might end up in the X session log file,
  resulting in duplicate logging. On Windows, it is pointless as well because bitcoin-qt isn't a console application.

  This same mechanism is used to set `-server` to true by default for bitcoind: https://github.com/bitcoin/bitcoin/blob/master/src/bitcoind.cpp#L116

  (fixes #13004)

Tree-SHA512: 24ae460d9d97130a063f7bf7fa6da1e6cc46643a94ea0827aa64d0f4a80647e5e7394695b24ea0f49a147a1fa07329659d224f04511fc24b97a9869d1c29b890

src/qt/bitcoin.cpp

@@ -403,6 +403,10 @@ void BitcoinApplication::startThread()
 
 void BitcoinApplication::parameterSetup()
 {
+    // Default printtoconsole to false for the GUI. GUI programs should not
+    // print to the console unnecessarily.
+    gArgs.SoftSetBoolArg("-printtoconsole", false);
+
     m_node.initLogging();
     m_node.initParameterInteraction();
 }