[llvm] [SPIR-V] Add NonSemantic.AuxData emission (-spirv-preserve-auxdata) and preserve available_externally linkage (PR #200002)

[Dmitry Sidorov via llvm-commits]

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@@ -0,0 +1,58 @@
+; available_externally functions are emitted as definitions with Export
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MrSidims wrote:

I believe available_externally GVs are not handled in the patch.

https://github.com/llvm/llvm-project/pull/200002