[compiler-rt] [sanitizer-common] [Darwin] Provide warnings for common sandbox issues (PR #165907)

[Dan Blackwell via llvm-commits]

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@@ -505,6 +505,13 @@ static void ChooseSymbolizerTools(IntrusiveList<SymbolizerTool> *list,
   }
 
 #  if SANITIZER_APPLE
+  if (list.size() == 0) {
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DanBlackwell wrote:

NIT: we have a `.empty()` for this, right? https://github.com/llvm/llvm-project/blob/d2625a438020ad35330cda29c3def102c1687b1b/compiler-rt/lib/sanitizer_common/sanitizer_list.h#L36
I think that using this would better convey the intention.

https://github.com/llvm/llvm-project/pull/165907