[libcxx-commits] [libcxx] Revert "[libc++] Don't try to be compatible with libstdc++ in __libcpp_refstring on iOS (#170816)" (PR #173099)

[Louis Dionne via libcxx-commits]

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@@ -25,7 +25,7 @@
 // string singleton before manipulating the reference count. This is done so that
 // if an exception is created with a zero-length string in libstdc++, libc++abi
 // won't try to delete the memory.
-#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)
+#if defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__) || defined(__ENVIRONMENT_IPHONE_OS_VERSION_MIN_REQUIRED__)
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ldionne wrote:

That being said, I am still investigating whether we can get rid of this for macOS on arm64. I think we'll be able to.

If that's the case, we'd have to support this on iOS arm64 and on macOS x86_64.

https://github.com/llvm/llvm-project/pull/173099