Feature Request: Expose PU APIC ID in hwloc API

[rsagashe03]

I’d like to request support for exposing the APIC ID of Processing Units (PUs) through the public hwloc API.

Currently, APIC IDs are discovered and stored internally by the x86 backend (e.g., in struct procinfo as infos[i].apicid), but this data is not made accessible through the public API.

Motivation:APIC IDs are useful for many low-level system programming tasks:

It is stable across OSes because it's independent of it, and thus it can also be matched to BIOS/UEFI content.

pinning threads to specific dies or cores based on APIC layout

Proposed Solution:

It would be helpful if hwloc could make the APIC ID available through the below option:

Add an apic_id field to the hwloc_obj->attr structure for PU objects