[llvm] Sketch of build and code changes for llvm shared library build using explicit visibility annotations (PR #96630)

[Thomas Fransham via llvm-commits]

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@@ -81,3 +81,8 @@ endif()
 add_library(LLVMSupportBlake3 OBJECT EXCLUDE_FROM_ALL ${LLVM_BLAKE3_FILES})
 set_target_properties(LLVMSupportBlake3 PROPERTIES FOLDER "LLVM/Libraries")
 llvm_update_compile_flags(LLVMSupportBlake3)
+
+# We have to manually set this because this library was not created with llvm_add_library
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fsfod wrote:

My best guess is because it a bunch of C code and assembly files that need custom file options

https://github.com/llvm/llvm-project/pull/96630