[libc++] Add an option to disable wide character support in libc++
Some embedded platforms do not wish to support the C library functionality
for handling wchar_t because they have no use for it. It makes sense for
libc++ to work properly on those platforms, so this commit adds a carve-out
of functionality for wchar_t.
Unfortunately, unlike some other carve-outs (e.g. random device), this
patch touches several parts of the library. However, despite the wide
impact of this patch, I still think it is important to support this
configuration since it makes it much simpler to port libc++ to some
embedded platforms.
Differential Revision: https://reviews.llvm.org/D111265
NOKEYCHECK=True
GitOrigin-RevId: f4c1258d5633fcf06385ff3fd1f4bf57ab971964
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 1ec7fa3..1ffd5b4 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -49,7 +49,9 @@
API Changes
-----------
-- ...
+- Support for building libc++ on top of a C Standard Library that does not support ``wchar_t`` was
+ added. This is useful for building libc++ in an embedded setting, and it adds itself to the various
+ freestanding-friendly options provided by libc++.
Build System Changes
--------------------