[lld] [LLD][COFF] Add -build-id flag to generate .buildid section. (PR #71433)

[Zequan Wu via llvm-commits]

https://github.com/ZequanWu commented:

> There's some restructurings for how the different hashes/structures are made (I presume since you're not reusing the chunks but creating two separate sets, if needed) - have you checked that the output is binary identical to before (where applicable)?

Oh, I found a bug that it generates .buildid when it shouldn't. It's complicated on how those flags interacting with each other. After the fix, the output binary is identical to before when not generating pdb and with `/Brepro`. With PDB, the PDB content hash in debug directory are different which also happens on lld without any changes, maybe executable file name is part of the PDB hashing. (the only difference is executable names when comparing)

https://github.com/llvm/llvm-project/pull/71433