MacPorts GCC 4.8.2 error with mmacosx-version-min and Foundation headers

Question

I'm running 10.9.2 and installed GCC 4.8.2 through MacPorts (sudo port install gcc48 +universal) and cannot compile Objective-C code that sets -mmacosx-version-min=10.8 or any other version and includes Foundation. If I set the version to 10.9 or don't set it at all, it works.

Here's the code:

#include <Foundation/Foundation.h>
int main() {
    return 0;
}

Here's the command:

g++-mp-4.8 objctest.m -mmacosx-version-min=10.8 -framework Foundation

The error I receive is:

In file included from /usr/include/Availability.h:148:0,
             from /opt/local/lib/gcc48/gcc/x86_64-apple-darwin13/4.8.2/include-fixed/math.h:46,
             from /System/Library/Frameworks/CoreFoundation.framework/Headers/CoreFoundation.h:19,
             from /System/Library/Frameworks/Foundation.framework/Headers/Foundation.h:6,
             from objctest.m:1:
/System/Library/Frameworks/Foundation.framework/Headers/NSUserNotification.h:16:45: error: expected ',' or '}' before '__attribute__'
 NSUserNotificationActivationTypeReplied NS_AVAILABLE(10_9, NA) = 3
                                         ^

Even if I add the -isysroot arg like so:

-isysroot `xcodebuild -version -sdk macosx Path` 

It still doesn't work (although it gives errors relative to the SDK).

Is the MacPorts GCC borked or is this an issue with GCC and OS X headers?

My end goal is to compile a full program (Qt gui) for 10.6 that uses C++11 features, so GCC is a must as 10.6 doesn't have libc++.

Update 1: OS X's headers apply __attribute__((weak_import)) to an individual enumeration type, and GCC apparently doesn't support this:

For an enum, struct or union type, you may specify attributes either between the enum, struct or union tag and the name of the type, or just past the closing curly brace of the definition.

I don't want to patch SDK headers, so looks like this is a no-go.

Update 2: It is a documented Clang extension:

Clang allows attributes to be written on individual enumerators. This allows enumerators to be deprecated, made unavailable, etc. The attribute must appear after the enumerator name and before any initializer

Answer 1

You've got a problem trying to use the framework headers with gcc-4.8. The thing that it's complaining about is the presence of an attribute on an enumerator e.g.

enum foo {
   foo_alice = 1,
   foo_bob = 2,
   foo_carol __attribute__((deprecated)) = 3
};

but gcc doesn't support this; it's a clang extension. Normally gcc would massage headers to make them work, but it would only affect the system headers and not framework headers.

I'm just wondering about why you're trying to compile Objective-C code when Qt is C++, and, I would hope, does not depend on Objective-C features.