[llvm] [CodeGen] Expose the extensibility of PassConfig to plugins (PR #139059)

[Stefan Gränitz via llvm-commits]

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@@ -0,0 +1,16 @@
+if (NOT WIN32 AND NOT CYGWIN)
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weliveindetail wrote:

Never saw file headers in CMakeLists.txt, is it a thing?

https://github.com/llvm/llvm-project/pull/139059