[libc++] Remove the ability to use the std::nullptr_t emulation in C++03 mode
Back in https://reviews.llvm.org/D109459, we stopped using the C++03
emulation for std::nullptr_t by default, which was an ABI break. We
still left a knob for users to turn it back on if they were broken by
the change, with a note that we would remove that knob after one release.
The time has now come to remove the knob and clean up the std::nullptr_t
emulation.
Differential Revision: https://reviews.llvm.org/D114786
NOKEYCHECK=True
GitOrigin-RevId: 157bbe6aea22e87c822f6cda3cd404b8f657dce4
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 867cb0f..6ad7fe9 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -44,5 +44,10 @@
ABI Changes
-----------
+- The ``_LIBCPP_ABI_USE_CXX03_NULLPTR_EMULATION`` macro controlling whether we use an
+ emulation for ``std::nullptr_t`` in C++03 mode has been removed. After this change,
+ ``_LIBCPP_ABI_USE_CXX03_NULLPTR_EMULATION`` will not be honoured anymore and there
+ will be no way to opt back into the C++03 emulation of ``std::nullptr_t``.
+
Build System Changes
--------------------