Hello

We have observed a build failure related to aufs-util (version aufs5.8) on buildroot 2022.02.2 and 2022.05-rc2. Attempts at fixing the problem ourselves were unsuccessful, since the errors just kept on coming. You fix one, another pops up. The first error:

```
In file included from /root/test2/buildroot-2022.02.2/output/build/linux-5.15.18/include/uapi/linux/posix_types.h:5,
                 from /root/test2/buildroot-2022.02.2/output/build/linux-5.15.18/include/uapi/linux/types.h:14,
                 from /root/test2/buildroot-2022.02.2/output/build/linux-5.15.18/include/uapi/linux/stat.h:5,
                 from /usr/include/x86_64-linux-gnu/bits/statx.h:31,
                 from /usr/include/x86_64-linux-gnu/sys/stat.h:446,
                 from /usr/include/ftw.h:28,
                 from au_util.h:23,
                 from ver.c:25:
/root/test2/buildroot-2022.02.2/output/build/linux-5.15.18/include/uapi/linux/stddef.h:2:10: fatal error: linux/compiler_types.h: No such file or directory
    2 | #include <linux/compiler_types.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
```

We fixed this by modifying the include paths, but then the second error came:

```
gcc: error: pre: No such file or directory
make[1]: *** [<builtin>: c2sh] Error 1
```

This was fixed by creating an empty file called pre in the aufs-util build directory, but then, we got this error instead:

```
make[2]: *** No rule to make target '../extlib/glibc/error_at_line.h', needed by 'libau.o'.  Stop.
make[2]: Leaving directory '/root/test/buildroot-2022.05-rc2/output/build/aufs-util-aufs5.8/libau'
make[1]: *** [Makefile:106: all] Error 2
```

At this point we gave up trying to fix this ourselves.

Regards