bpo-36635: Change pyport.h for Py_BUILD_CORE_MODULE define (GH-12853)

Change PyAPI_FUNC(type), PyAPI_DATA(type) and PyMODINIT_FUNC macros
of pyport.h when Py_BUILD_CORE_MODULE is defined.

The Py_BUILD_CORE_MODULE define must be now be used to build a C
extension as a dynamic library accessing Python internals: export the
PyInit_xxx() function in DLL exports on Windows.

Changes:

* Py_BUILD_CORE_BUILTIN and Py_BUILD_CORE_MODULE now imply
  Py_BUILD_CORE directy in pyport.h.
* ceval.c compilation now fails with an error if Py_BUILD_CORE is not
  defined, just to ensure that Python is build with the correct
  defines.
* setup.py now compiles _pickle.c with Py_BUILD_CORE_MODULE define.
* setup.py compiles _json.c with Py_BUILD_CORE_MODULE define, rather
  than Py_BUILD_CORE_BUILTIN define
* PCbuild/pythoncore.vcxproj: Add Py_BUILD_CORE_BUILTIN define.

1 files changed, 3 insertions, 3 deletions

diff --git a/setup.py b/setup.py
index 9c83914fd9..c470719a6a 100644
--- a/setup.py
+++ b/setup.py
@@ -725,13 +725,13 @@ class PyBuildExt(build_ext):
         # heapq
         self.add(Extension("_heapq", ["_heapqmodule.c"]))
         # C-optimized pickle replacement
-        self.add(Extension("_pickle", ["_pickle.c"]))
+        self.add(Extension("_pickle", ["_pickle.c"],
+                           extra_compile_args=['-D Py_BUILD_CORE_MODULE']))
         # atexit
         self.add(Extension("atexit", ["atexitmodule.c"]))
         # _json speedups
         self.add(Extension("_json", ["_json.c"],
-                           # pycore_accu.h requires Py_BUILD_CORE_BUILTIN
-                           extra_compile_args=['-DPy_BUILD_CORE_BUILTIN']))
+                           extra_compile_args=['-D Py_BUILD_CORE_MODULE']))
 
         # profiler (_lsprof is for cProfile.py)
         self.add(Extension('_lsprof', ['_lsprof.c', 'rotatingtree.c']))