Doc: update abi3t build tool support

Doc/howto/abi3t-migration.rst

@@ -169,13 +169,18 @@ or :c:member:`PyTypeObject.tp_itemsize`), it cannot be ported to
 ``abi3t`` 3.15.
 
 
+.. _abi3t-migration-build:
+
 Setting up the build
 ====================
 
-If you use a build tool (such as setuptools, meson-python, scikit-build-core),
-search its documentation for a way to select ``abi3t``.
-At the time of writing, not all of them have this; but if your tool does,
-use it.
+If your build tool supports ``abi3t``, use it to select the ABI.
+See the documentation for `meson-python
+<https://mesonbuild.com/meson-python/how-to-guides/limited-api.html#the-abi3t-stable-abi>`__,
+`scikit-build-core
+<https://scikit-build-core.readthedocs.io/en/stable/configuration/#customizing-the-output-wheel>`__,
+and `Maturin <https://www.maturin.rs/bindings#py_limited_apiabi3>`__,
+all of which support ``abi3t``.
 You may want to verify that it set the right flag by temporarily adding the
 following just after ``#include <Python.h>``::
 
@@ -185,6 +190,13 @@ following just after ``#include <Python.h>``::
 
 This should result in a different error than "``abi3t`` define is not set".
 
+.. seealso::
+
+   `Building and distributing abi3t extensions
+   <https://py-free-threading.github.io/abi3t/>`__:
+   Build configuration and wheel testing examples in the community-maintained
+   Python Free-Threading Guide.
+
 .. note::
 
    If your build tool doesn't support ``abi3t`` yet, set the following macro

Doc/whatsnew/3.15.rst

@@ -572,16 +572,19 @@ the existing Stable ABI (``abi3``) and the version-specific ABI for
 free-threading (``cp315t``) separately.
 
 Stable ABI for Free-Threaded Builds should typically
-be selected in a build tool (such as, for example, Setuptools, meson-python,
-scikit-build-core, or Maturin).
-At the time of writing, these tools do **not** support ``abi3t``.
-If this is the case for your tool, compile for ``cp315t`` separately.
+be selected in a build tool. Tools with ``abi3t`` support include
+meson-python, scikit-build-core, and Maturin; see
+:ref:`abi3t-migration-build` for links to their documentation on ``abi3t`` builds.
+If your build tool does not support ``abi3t``, compile for ``cp315t`` separately.
 If not using a build tool -- or when writing such a tool -- you can select
 ``abi3t`` by setting the macro :c:macro:`!Py_TARGET_ABI3T` as discussed
 in :ref:`abi3-compiling`.
 
 A practical :ref:`migration guide <abi3t-migration-howto>` for switching to
 ``abi3t`` is available.
+The community-maintained `Python Free-Threading Guide
+<https://py-free-threading.github.io/abi3t/>`__ provides examples of building
+and testing ``abi3t`` wheels.
 
 .. seealso:: :pep:`803` for further details.