[PATCH] aarch64: define struct user_pac_mask if needed

[Mark Wielaard]

Hi Markus,

On Fri, Feb 21, 2025 at 11:19:34AM -0800, Markus Mayer wrote:
> On Aarch64, Linux is using Pointer Authentication Code (PAC) for pointer
> authentication.[1] The struct "user_pac_mask" has been part of the Linux
> kernel since version 5.0 as part of this feature. However, older kernels
> do not define it.
> 
> Therefore, we want to check if the definition is present in the kernel
> headers and provide one if it isn't. This ensures two things:
> 
> * elfutils will continue to compile against kernel headers from 4.x
> * binaries built against older kernel headers will still be fully
>   functional if used on a newer system

This looks very nice.  I added a reference to
https://sourceware.org/bugzilla/show_bug.cgi?id=32684 to the commit
message and pushed your commit.

Thanks,

Mark