[llvm] [lld] [llvm-lib][llvm-dlltool][Object] Add support for EXPORTAS name types. (PR #78772)

[Jacek Caban via llvm-commits]

cjacek wrote:

I meant llvm-dlltool. You're right, GNU dlltool indeed uses a regular COFF object to achieve essentially the same result.

That makes EXPORTAS a potential replacement for using weak externals. I don't think we want to change that by default as it would break compatibility with linkers that don't support EXPORTAS. However, doing that for ARM64EC, which has additional auxiliary IAT symbols, seems right.

https://github.com/llvm/llvm-project/pull/78772