[runtimes] Remove FOO_TARGET_TRIPLE, FOO_SYSROOT and FOO_GCC_TOOLCHAIN
Instead, folks can use the equivalent variables provided by CMake
to set those. This removal aims to reduce complexity and potential
for confusion when setting the target triple for building the runtimes,
and make it correct when `CMAKE_OSX_ARCHITECTURES` is used (right now
both `-arch` and `--target=` will end up being passed, which is downright
incorrect).
Differential Revision: https://reviews.llvm.org/D112155
NOKEYCHECK=True
GitOrigin-RevId: 3ee0cec88effc88285732c8bec2a8f0e4e37c0b1
diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 4228067..eb85502 100644
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -79,3 +79,8 @@
- Support for standalone builds have been entirely removed from libc++, libc++abi and
libunwind. Please use :ref:`these instructions <build instructions>` for building
libc++, libc++abi and/or libunwind.
+
+- The ``{LIBCXX,LIBCXXABI,LIBUNWIND}_TARGET_TRIPLE``, ``{LIBCXX,LIBCXXABI,LIBUNWIND}_SYSROOT`` and
+ ``{LIBCXX,LIBCXXABI,LIBUNWIND}_GCC_TOOLCHAIN`` CMake variables have been removed. Instead, please
+ use the ``CMAKE_CXX_COMPILER_TARGET``, ``CMAKE_SYSROOT`` and ``CMAKE_CXX_COMPILER_EXTERNAL_TOOLCHAIN``
+ variables provided by CMake.