[libc++] Use XXYYZZ instead of XXYZZ for _LIBCPP_VERSION
As discussed on Discord.
Differential Revision: https://reviews.llvm.org/D134209
NOKEYCHECK=True
GitOrigin-RevId: b6ff5b470d5e4acfde59d57f18e575c0284941f4
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 2b1683a..aad7dba 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -86,6 +86,12 @@
Any standards-required ``[[nodiscard]]`` applications in C++20 are now always enabled. Any extended applications
are now enabled by default and can be disabled by defining ``_LIBCPP_DISABLE_NODISCARD_EXT``.
+- ``_LIBCPP_VERSION`` was previously defined to e.g. ``15001`` to represent LLVM 15.0.01, but this value had been
+ left undocumented. Starting with LLVM 16, ``_LIBCPP_VERSION`` will contain the version of LLVM represented as
+ ``XXYYZZ``. In other words, ``_LIBCPP_VERSION`` is gaining a digit. This should not be an issue for existing
+ code, since using e.g. ``_LIBCPP_VERSION > 15000`` will still give the right answer now that ``_LIBCPP_VERSION``
+ is defined as e.g. ``160000`` (with one more digit).
+
ABI Affecting Changes
---------------------
- In freestanding mode, ``atomic<small enum class>`` does not contain a lock byte anymore if the platform