Invalid position of G_NORETURN in clang v15

Host environment

• Operating system: Arch Linux
• OS/kernel version: Linux $HOST 6.2.5-zen1-1-zen #1 ZEN SMP PREEMPT_DYNAMIC Sat, 11 Mar 2023 14:28:15 +0000 x86_64 GNU/Linux
• Architecture: x86_64
• QEMU flavor: qemu-system-mipsel
• QEMU version: v7.1.0 / master

Description of problem

Order of G_NORETURN used in https://gitlab.com/qemu-project/qemu/-/blob/0f3de970febd2c9b29dccecb63ca928c6802a101/include/qemu/osdep.h#L240-242 is not valid in clang++ 15.0.7.

Switching extern with G_NORETURN seems to fix the issue.

Steps to reproduce

1. Build qemu system for MIPSEL or use minimal reproducer:

example.cpp:

#include "/path/to/qemu/include/glib-compat.h"

extern G_NORETURN
void // QEMU_ERROR("code path is reachable")
    qemu_build_not_reached_always(void);

$ clang++ --version
clang version 15.0.7
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ clang++ -m64 -mcx16 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -fcolor-diagnostics -Wall -Winvalid-pch -std=gnu++11 -O0 -g example.cpp
example.cpp:3:8: error: an attribute list cannot appear here
extern G_NORETURN
       ^~~~~~~~~~
/usr/include/glib-2.0/glib/gmacros.h:1075:21: note: expanded from macro 'G_NORETURN'
# define G_NORETURN [[noreturn]]
                    ^~~~~~~~~~~~
1 error generated.