Activate breeze-dark on Windows for darkMode

Use libkleo SystemInfo to check for dark mode and
activate breeze-dark theme in that case on Windows.

GnuPG-Bug-Id: T6076

CMakeLists.txt

@@ -34,7 +34,7 @@ set(KF5_MIN_VERSION "5.97.0")
 set(KIDENTITYMANAGEMENT_VERSION "5.21.40")
 set(KMAILTRANSPORT_VERSION "5.21.40")
 set(KMIME_VERSION "5.21.40")
-set(LIBKLEO_VERSION "5.21.46")
+set(LIBKLEO_VERSION "5.21.47")
 set(QT_REQUIRED_VERSION "5.15.2")
 set(GPGME_REQUIRED_VERSION "1.16.0")
 

src/kleopatraapplication.cpp

@@ -35,6 +35,7 @@
 #include <Libkleo/KeyFilterManager>
 #include <Libkleo/KeyGroupConfig>
 #include <Libkleo/Classify>
+#include <Libkleo/SystemInfo>
 
 #ifdef HAVE_USABLE_ASSUAN
 # include <uiserver/uiserver.h>
@@ -328,6 +329,13 @@ void KleopatraApplication::init()
     d->setUpSysTrayIcon();
     d->setUpFilterManager();
     d->setupLogging();
+#ifdef Q_OS_WIN
+    // Under Linux the Theme is set outside. On Windows we have to do
+    // it ourself.
+    if (SystemInfo::isDarkModeActive()) {
+        QIcon::setThemeName("breeze-dark");
+    }
+#endif
 #ifndef QT_NO_SYSTEMTRAYICON
     d->sysTray->show();
 #endif