[clang] [Clang] Add codegen option to add passbuilder callback functions (PR #70171)

[Arthur Eubanks via cfe-commits]

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@@ -0,0 +1,23 @@
+# If we don't need RTTI or EH, there's no reason to export anything
+# from the plugin.
+if( NOT MSVC ) # MSVC mangles symbols differently, and
+    # PrintLLVMFunctionNames.export contains C++ symbols.
+  if( NOT LLVM_REQUIRES_RTTI )
+    if( NOT LLVM_REQUIRES_EH )
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aeubanks wrote:

nit: spaces after `if` are inconsistent 

https://github.com/llvm/llvm-project/pull/70171