cleanup: run XCode code analysis

enable ARC in CMakelist.txt
fix small potentials leaks across the client

Refs #75600

Change-Id: I72ba17e6daed393abdf38653f45c040bd3427ead
diff --git a/src/PreferencesVC.h b/src/PreferencesVC.h
index e763caa..4b2ecf9 100644
--- a/src/PreferencesVC.h
+++ b/src/PreferencesVC.h
@@ -34,11 +34,11 @@
 
 @interface PreferencesVC : NSViewController <NSToolbarDelegate>
 
-@property (nonatomic, assign) NSViewController *currentVC;
-@property (nonatomic, assign) NSViewController *accountsPrefsVC;
-@property (nonatomic, assign) NSViewController *generalPrefsVC;
-@property (nonatomic, assign) NSViewController *audioPrefsVC;
-@property (nonatomic, assign) NSViewController *videoPrefsVC;
+@property (nonatomic, strong) NSViewController *currentVC;
+@property (nonatomic, strong) NSViewController *accountsPrefsVC;
+@property (nonatomic, strong) NSViewController *generalPrefsVC;
+@property (nonatomic, strong) NSViewController *audioPrefsVC;
+@property (nonatomic, strong) NSViewController *videoPrefsVC;
 
 - (void) close;
 - (void)displayGeneral:(NSToolbarItem *)sender;