Add _mac suffix for obj-c files.

browser/atom_application_delegate_mac.mm

@@ -0,0 +1,24 @@
+// Copyright (c) 2013 GitHub, Inc. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "browser/atom_application_delegate_mac.h"
+
+#import "browser/atom_application_mac.h"
+
+@implementation AtomApplicationDelegate
+
+- (void)applicationDidFinishLaunching:(NSNotification*)notify {
+  NSAppleEventManager* em = [NSAppleEventManager sharedAppleEventManager];
+  [em setEventHandler:self
+          andSelector:@selector(handleQuitEvent:withReplyEvent:)
+        forEventClass:kCoreEventClass
+           andEventID:kAEQuitApplication];
+}
+
+- (void)handleQuitEvent:(NSAppleEventDescriptor*)event
+         withReplyEvent:(NSAppleEventDescriptor*)replyEvent {
+  [[AtomApplication sharedApplication] closeAllWindows:self];
+}
+
+@end