[llvm] [Object,ELF] Implement PN_XNUM extension for program headers (PR #162288)

[via llvm-commits]

aokblast wrote:

@jh7370 I am sorry that I mass up the commit again and I think the automerge won't work because of the duplicate commit as I show in the picture. Could you please accept this totally same branch in https://github.com/llvm/llvm-project/pull/165284?

<img width="1713" height="1124" alt="CleanShot 2025-10-31 at 00 49 06" src="https://github.com/user-attachments/assets/bd949db7-257c-4f5f-a4b1-b4fe1cf5b271" />


https://github.com/llvm/llvm-project/pull/162288