Add linkage and implementation sections.

pep-0384.txt

@@ -238,6 +238,39 @@ In addition, the following macros are available:
 - Py_BEGIN_ALLOW_THREADS, Py_BLOCK_THREADS, Py_UNBLOCK_THREADS,
   Py_END_ALLOW_THREADS
 
+Linkage
+-------
+
+On Windows, applications shall link with python3.dll; an import
+library python3.lib will be available. This DLL will redirect all of
+its API functions through /export linker options to the full
+interpreter DLL, i.e. python3y.dll.
+
+XXX is it possible to redirect global variables in the same way?
+If not, python3.dll would have to copy them, and we should verify
+that all available global variables are read-only.
+
+On Unix systems, the ABI is typically provided by the python
+executable itself. PyModule_Create is changed to pass ``3`` as the API
+version if the extension module was compiled with Py_LIMITED_API; the
+version check for the API version will accept either 3 or the current
+PYTHON_API_VERSION as conforming. If Python is compiled as a shared
+library, it is installed as both libpython3.so, and libpython3.y.so;
+applications conforming to this PEP should then link to the former.
+
+XXX is it possible to make the soname libpython.so.3, and still
+have some applications link to libpython3.y.so?
+
+Implementation Strategy
+=======================
+
+This PEP will be implemented in a branch, allowing users to check
+whether their modules conform to the ABI. To simplify this testing, an
+additional macro Py_LIMITED_API_WITH_TYPES will expose the existing
+type object layout, to let users postpone rewriting all types. When
+the this branch is merged into the 3.2 code base, this macro will
+be removed.
+
 Copyright
 =========