The following patch was taken from upstream:
https://qt.gitorious.org/qt/qtbase/commit/70e4428b6f1c6a4bad112203f67ee7d22107616c.patch

The first hunk was removed because it conflicts with 5.2.1, and is not currently needed.

From 70e4428b6f1c6a4bad112203f67ee7d22107616c Mon Sep 17 00:00:00 2001
From: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Date: Tue, 3 Jun 2014 14:20:20 +0200
Subject: [PATCH] Cocoa: Adapt to Xcode 6 clang version sudden pickiness
MIME-Version: 1.0
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Yes, that means OS X Yosemite fix.

Change-Id: I236f7af7b803de24ff0895e04c9a9253b5cfdb3b
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
---
 .../platforms/cocoa/qcocoaaccessibilityelement.mm  |    2 +-
 .../platforms/cocoa/qcocoaapplicationdelegate.mm   |    2 +-
 src/plugins/platforms/cocoa/qcocoamenuloader.mm    |    2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm b/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
index f841184..548c6a2 100644
--- a/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
+++ b/src/plugins/platforms/cocoa/qcocoaapplicationdelegate.mm
@@ -124,7 +124,7 @@ static void cleanupCocoaApplicationDelegate()
     [dockMenu release];
     [qtMenuLoader release];
     if (reflectionDelegate) {
-        [NSApp setDelegate:reflectionDelegate];
+        [[NSApplication sharedApplication] setDelegate:reflectionDelegate];
         [reflectionDelegate release];
     }
     [[NSNotificationCenter defaultCenter] removeObserver:self];
diff --git a/src/plugins/platforms/cocoa/qcocoamenuloader.mm b/src/plugins/platforms/cocoa/qcocoamenuloader.mm
index 60bc3b5..9340e94 100644
--- a/src/plugins/platforms/cocoa/qcocoamenuloader.mm
+++ b/src/plugins/platforms/cocoa/qcocoamenuloader.mm
@@ -174,7 +174,7 @@ QT_END_NAMESPACE
 - (void)removeActionsFromAppMenu
 {
     for (NSMenuItem *item in [appMenu itemArray])
-        [item setTag:nil];
+        [item setTag:0];
 }
 
 - (void)dealloc
-- 
1.7.1

