[lld] [lld][ELF] Add --debug-names to create merged .debug_names. (PR #86508)

[via llvm-commits]

cmtice wrote:

> > I have now brought over all the changes from maskray's branch, and also updated the commit message as requested. I believe this is ready for reviews now.
> 
> I've noticed that the current commit stack doesn't include any commits directly authored by me (note: committer information is completely ignored by github).
> 
> To make the collaboration history clearer, I'd recommend resetting the commit to https://github.com/MaskRay/llvm-project/tree/lld-debug-names-for-cmtice. This way, your comment changes will be easily attributed to you. There are a few key modifications we can still discuss to reach an optimal solution.
> 
> While simply adding "This work was co-authored with maskray." wouldn't suffice, including the following message would accurately reflect my contributions:
> 
> ```
> Co-authored-by: Fangrui Song <i at maskray.me>
> ```
> 
> (This is why I previously suggested adopting the commit message from https://github.com/MaskRay/llvm-project/commits/lld-debug-names/ verbatimly.)
> 
> (Under normal circumstances, even with extensive edits, I wouldn't typically request co-authorship. However, in this specific case, the significant amount of time and effort I've invested, including performance enhancements, bug fixes, and substantial style changes, hopefully warrants co-author credit. The current top commit doesn't fully reflect this level of involvement.)
> 
> This is why I suggested I create a new PR. I shall hopefully credit authorship precisely and make relevant changes in a timely manner.

Ok, I have updated this as you requested (I think), so hopefully you will now get proper credit for all the work you have done (thank you for that)! 

https://github.com/llvm/llvm-project/pull/86508