SYNERGY-691 Systray icon is incorrect for macOS Big Sur (#6944)

* SYNERGY-691 Systray icon is incorrect for macOS Big Sur

* Update ChangeLog

ChangeLog

@@ -13,6 +13,7 @@ Bug fixes:
 - #6936 Application loses settings
 - #6939 Update pipelines to use correct credentials
 - #6942 All the text in all the windows should have the same font and size
+- #6944 Systray icon is incorrect for macOS Big Sur
 
 Enhancements:
 - #6912 Removes UI for Screen Saver Sync and Files Drag and Drop

src/gui/src/MainWindow.cpp

@@ -360,7 +360,7 @@ void MainWindow::setIcon(qSynergyState state) const
     QIcon icon;
 
 #ifdef Q_OS_MAC
-    if (isOSXInterfaceStyleDark())
+    if (isOSXUseDarkIcons())
         icon.addFile(synergyDarkIconFiles[state]);
     else
         icon.addFile(synergyLightIconFiles[state]);

src/gui/src/OSXHelpers.h

@@ -20,5 +20,6 @@
 #define OSXHELPERS__H
 
 bool isOSXInterfaceStyleDark();
+bool isOSXUseDarkIcons();
 
 #endif

src/gui/src/OSXHelpers.mm

@@ -24,8 +24,19 @@
 bool
 isOSXInterfaceStyleDark()
 {
-	// Implementation from http://stackoverflow.com/a/26472651
-	NSDictionary* dict = [[NSUserDefaults standardUserDefaults] persistentDomainForName:NSGlobalDomain];
-	id style = [dict objectForKey:@"AppleInterfaceStyle"];
-	return (style && [style isKindOfClass:[NSString class]] && NSOrderedSame == [style caseInsensitiveCompare:@"dark"]);
+   // Implementation from http://stackoverflow.com/a/26472651
+   NSDictionary* dict = [[NSUserDefaults standardUserDefaults] persistentDomainForName:NSGlobalDomain];
+   id style = [dict objectForKey:@"AppleInterfaceStyle"];
+   return (style && [style isKindOfClass:[NSString class]] && NSOrderedSame == [style caseInsensitiveCompare:@"dark"]);
+}
+
+bool
+isOSXUseDarkIcons()
+{
+   if (@available(macOS 11, *)) {
+      return true;
+   }
+   else {
+      return isOSXInterfaceStyleDark();
+   }
 }