xcode: Drop use of weak_import on enumerators.

GCC doesn't support attributes on enumerators, which could pose a
problem but fortunately not in this case. Here a
__attribute__((weak_import)) is used, which doesn't make much sense for
enumerators anyway (noone will die because the corresponding enumerator
won't be referenced either in older OS X versions).

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/os-specific/darwin/xcode/gcc-fix-enum-attributes.patch

@@ -0,0 +1,13 @@
+diff --git a/System/Library/Frameworks/Foundation.framework/Headers/NSUserNotification.h b/System/Library/Frameworks/Foundation.framework/Headers/NSUserNotification.h
+index fa0c290..7da7e0c 100644
+--- a/System/Library/Frameworks/Foundation.framework/Headers/NSUserNotification.h
++++ b/System/Library/Frameworks/Foundation.framework/Headers/NSUserNotification.h
+@@ -13,7 +13,7 @@ typedef NS_ENUM(NSInteger, NSUserNotificationActivationType) {
+     NSUserNotificationActivationTypeNone = 0,
+     NSUserNotificationActivationTypeContentsClicked = 1,
+     NSUserNotificationActivationTypeActionButtonClicked = 2,
+-    NSUserNotificationActivationTypeReplied NS_AVAILABLE(10_9, NA) = 3
++    NSUserNotificationActivationTypeReplied = 3
+ } NS_ENUM_AVAILABLE(10_8, NA);
+ 
+ NS_CLASS_AVAILABLE(10_8, NA)