fix: use consistent Q_OS_WIN macro for Windows platform detection

Author: kwsantiago

src/qt/bitcoingui.cpp

@@ -253,6 +253,9 @@ BitcoinGUI::~BitcoinGUI()
     delete m_app_nap_inhibitor;
     MacDockIconHandler::cleanup();
 #endif
+#ifdef BITCOIN_QT_WIN_TASKBAR
+    delete m_taskbar_progress;
+#endif
 
     delete NetWatch;
     delete rpcConsole;
@@ -1442,6 +1445,13 @@ void BitcoinGUI::showEvent(QShowEvent *event)
     showMempoolStatsAction->setEnabled(true);
     aboutAction->setEnabled(true);
     optionsAction->setEnabled(true);
+
+#ifdef BITCOIN_QT_WIN_TASKBAR
+    // If window handle wasn't available during construction, set it now
+    if (m_taskbar_progress && !m_taskbar_progress->window() && windowHandle()) {
+        m_taskbar_progress->setWindow(windowHandle());
+    }
+#endif
 }
 
 #ifdef ENABLE_WALLET

src/qt/wintaskbarprogress.h

@@ -5,7 +5,7 @@
 #ifndef BITCOIN_QT_WINTASKBARPROGRESS_H
 #define BITCOIN_QT_WINTASKBARPROGRESS_H
 
-#ifdef WIN32
+#ifdef Q_OS_WIN
 #include <QWindow>
 
 #include <windows.h>
@@ -27,6 +27,9 @@ class WinTaskbarProgress
     /** Set the window handle to attach progress to */
     void setWindow(QWindow* window);
 
+    /** Get the window handle */
+    QWindow* window() const { return m_window; }
+
     /** Set progress value (0-100) */
     void setValue(int value);
 
@@ -46,6 +49,6 @@ class WinTaskbarProgress
     void releaseTaskbar();
 };
 
-#endif // WIN32
+#endif // Q_OS_WIN
 
 #endif // BITCOIN_QT_WINTASKBARPROGRESS_H