Abjust wording to cover platform-specific optional modules

Author: encukou

Doc/glossary.rst

@@ -1030,8 +1030,9 @@ Glossary
       but may be absent in some builds of :term:`CPython`,
       usually due to missing third-party libraries or because the module
       is not available for a given platform.
+
       See :ref:`optional-module-requirements` for a list of optional modules
-      and the required libraries.
+      that require third-party libraries.
 
    package
       A Python :term:`module` which can contain submodules or recursively,

Doc/using/configure.rst

@@ -48,12 +48,13 @@ support".
 Requirements for optional modules
 ---------------------------------
 
-To build :term:`optional modules <optional module>` of the standard library,
-you will need several third-party libraries installed for development
+Some :term:`optional modules <optional module>` of the standard library
+require third-party libraries installed for development
 (for example, header files must be available).
 
 Missing requirements are reported in the ``configure`` output.
-Missing optional modules are listed near the end of the ``make`` output,
+Modules that are missing due to missing dependencies are listed near the end
+of the ``make`` output,
 sometimes using an internal name such as ``_ctypes`` for the :mod:`ctypes`
 module.
 
@@ -124,6 +125,9 @@ Dependencies to build optional modules are:
    bundled implementations of several hash functions.
    See :option:`--with-builtin-hashlib-hashes` for *forcing* usage of OpenSSL.
 
+Note that the table does not include all optional modules; in particular,
+platform-specific modules like :mod:`winreg` are not listed here.
+
 .. seealso::
 
    * The `devguide <https://devguide.python.org/getting-started/setup-building/#install-dependencies>`_