[clang] [Clang][HLSL] Add environment parameter to availability attribute (PR #89809)

[Helena Kotas via cfe-commits]

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@@ -0,0 +1,140 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel5.0-compute -fsyntax-only -verify %s
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hekota wrote:

Done.

https://github.com/llvm/llvm-project/pull/89809