a central links file

This makes it easier to move content around without worrying about where
the links are defined.  It will also be easier to have canonical links
that can be used from multiple places in the guide.

getting-started/setup-building.rst

@@ -784,9 +784,6 @@ some of CPython's modules (for example, ``zlib``).
    to the `macOS README
    <https://github.com/python/cpython/blob/main/Mac/README.rst>`_.
 
-   .. _clang: https://clang.llvm.org/
-   .. _ccache: https://ccache.dev/
-
    .. note:: While you need a C compiler to build CPython, you don't need any
       knowledge of the C language to contribute!  Vast areas of CPython are
       written completely in Python: as of this writing, CPython contains slightly
@@ -1001,8 +998,6 @@ every rule.
      Various tools that are (or have been) used to maintain Python.
 
 
-.. _issue tracker: https://github.com/python/cpython/issues
-
 
 .. _using-codespaces:
 
@@ -1071,3 +1066,6 @@ power may be a much higher spec than your local machine which can be helpful.
 
 
 .. TODO: add docker instructions
+
+
+.. include:: ../links.rst

links.rst

@@ -0,0 +1,6 @@
+.. Links for use anywhere.  Include this file to use them.
+
+.. _issue tracker: https://github.com/python/cpython/issues
+
+.. _clang: https://clang.llvm.org/
+.. _ccache: https://ccache.dev/