[llvm] Export empty vt_gen target (for standalone builds) (PR #109817)

[Saleem Abdulrasool via llvm-commits]

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@@ -33,6 +33,9 @@ endforeach(lib)
 if(intrinsics_gen IN_LIST LLVM_COMMON_DEPENDS)
   list(REMOVE_ITEM LLVM_COMMON_DEPENDS intrinsics_gen)
 endif()
+if(vt_gen IN_LIST LLVM_COMMON_DEPENDS)
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compnerd wrote:

Lexicographical ordering?

https://github.com/llvm/llvm-project/pull/109817