diff --git a/Include/internal/pycore_accu.h b/Include/internal/pycore_accu.h
index 4350db5..d346222 100644
--- a/Include/internal/pycore_accu.h
+++ b/Include/internal/pycore_accu.h
@@ -9,8 +9,8 @@
  *** Its definition may be changed or removed at any moment.
  ***/
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 /*
diff --git a/Include/internal/pycore_atomic.h b/Include/internal/pycore_atomic.h
index 7aa7eed..b3ec44c 100644
--- a/Include/internal/pycore_atomic.h
+++ b/Include/internal/pycore_atomic.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "dynamic_annotations.h"
diff --git a/Include/internal/pycore_ceval.h b/Include/internal/pycore_ceval.h
index 2ead96c..0bb19f1 100644
--- a/Include/internal/pycore_ceval.h
+++ b/Include/internal/pycore_ceval.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "pycore_atomic.h"
diff --git a/Include/internal/pycore_condvar.h b/Include/internal/pycore_condvar.h
index a12b699..8b89d70 100644
--- a/Include/internal/pycore_condvar.h
+++ b/Include/internal/pycore_condvar.h
@@ -1,8 +1,8 @@
 #ifndef Py_INTERNAL_CONDVAR_H
 #define Py_INTERNAL_CONDVAR_H
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #ifndef _POSIX_THREADS
diff --git a/Include/internal/pycore_context.h b/Include/internal/pycore_context.h
index 70701cd..5e1ba0d 100644
--- a/Include/internal/pycore_context.h
+++ b/Include/internal/pycore_context.h
@@ -1,8 +1,8 @@
 #ifndef Py_INTERNAL_CONTEXT_H
 #define Py_INTERNAL_CONTEXT_H
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "pycore_hamt.h"
diff --git a/Include/internal/pycore_coreconfig.h b/Include/internal/pycore_coreconfig.h
index 3a27628..3353844 100644
--- a/Include/internal/pycore_coreconfig.h
+++ b/Include/internal/pycore_coreconfig.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN defined"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 
diff --git a/Include/internal/pycore_getopt.h b/Include/internal/pycore_getopt.h
index 0d1897c..834b8c8 100644
--- a/Include/internal/pycore_getopt.h
+++ b/Include/internal/pycore_getopt.h
@@ -1,8 +1,8 @@
 #ifndef Py_INTERNAL_PYGETOPT_H
 #define Py_INTERNAL_PYGETOPT_H
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 extern int _PyOS_opterr;
diff --git a/Include/internal/pycore_gil.h b/Include/internal/pycore_gil.h
index 014e75f..7de3163 100644
--- a/Include/internal/pycore_gil.h
+++ b/Include/internal/pycore_gil.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "pycore_condvar.h"
diff --git a/Include/internal/pycore_hamt.h b/Include/internal/pycore_hamt.h
index 8b2ce1f..e65aef5 100644
--- a/Include/internal/pycore_hamt.h
+++ b/Include/internal/pycore_hamt.h
@@ -1,8 +1,8 @@
 #ifndef Py_INTERNAL_HAMT_H
 #define Py_INTERNAL_HAMT_H
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #define _Py_HAMT_MAX_TREE_DEPTH 7
diff --git a/Include/internal/pycore_object.h b/Include/internal/pycore_object.h
index c955953..81548f8 100644
--- a/Include/internal/pycore_object.h
+++ b/Include/internal/pycore_object.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN defined"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "pycore_pystate.h"   /* _PyRuntime */
diff --git a/Include/internal/pycore_pathconfig.h b/Include/internal/pycore_pathconfig.h
index 80d86a0..9eb8e88 100644
--- a/Include/internal/pycore_pathconfig.h
+++ b/Include/internal/pycore_pathconfig.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 typedef struct _PyPathConfig {
diff --git a/Include/internal/pycore_pyhash.h b/Include/internal/pycore_pyhash.h
index babbc95..a229f8d 100644
--- a/Include/internal/pycore_pyhash.h
+++ b/Include/internal/pycore_pyhash.h
@@ -1,8 +1,8 @@
 #ifndef Py_INTERNAL_HASH_H
 #define Py_INTERNAL_HASH_H
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 uint64_t _Py_KeyedHash(uint64_t, const char *, Py_ssize_t);
diff --git a/Include/internal/pycore_pylifecycle.h b/Include/internal/pycore_pylifecycle.h
index d837ea4..bfff24b 100644
--- a/Include/internal/pycore_pylifecycle.h
+++ b/Include/internal/pycore_pylifecycle.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 /* True if the main interpreter thread exited due to an unhandled
diff --git a/Include/internal/pycore_pymem.h b/Include/internal/pycore_pymem.h
index 8da1bd9..20f3b5e 100644
--- a/Include/internal/pycore_pymem.h
+++ b/Include/internal/pycore_pymem.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN defined"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "objimpl.h"
diff --git a/Include/internal/pycore_pystate.h b/Include/internal/pycore_pystate.h
index df3730f..e1ce08d 100644
--- a/Include/internal/pycore_pystate.h
+++ b/Include/internal/pycore_pystate.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "cpython/coreconfig.h"
diff --git a/Include/internal/pycore_tupleobject.h b/Include/internal/pycore_tupleobject.h
index d0c5b62..9fcfc5c 100644
--- a/Include/internal/pycore_tupleobject.h
+++ b/Include/internal/pycore_tupleobject.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "tupleobject.h"
diff --git a/Include/internal/pycore_warnings.h b/Include/internal/pycore_warnings.h
index 91bf902..73e5350 100644
--- a/Include/internal/pycore_warnings.h
+++ b/Include/internal/pycore_warnings.h
@@ -4,8 +4,8 @@
 extern "C" {
 #endif
 
-#if !defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_BUILTIN)
-#  error "this header requires Py_BUILD_CORE or Py_BUILD_CORE_BUILTIN define"
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
 #endif
 
 #include "object.h"
diff --git a/Include/pyport.h b/Include/pyport.h
index 4971a49..075b360 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -5,6 +5,27 @@
 
 #include <inttypes.h>
 
+
+/* Defines to build Python and its standard library:
+ *
+ * - Py_BUILD_CORE: Build Python core. Give access to Python internals, but
+ *   should not be used by third-party modules.
+ * - Py_BUILD_CORE_BUILTIN: Build a Python stdlib module as a built-in module.
+ * - Py_BUILD_CORE_MODULE: Build a Python stdlib module as a dynamic library.
+ *
+ * Py_BUILD_CORE_BUILTIN and Py_BUILD_CORE_MODULE imply Py_BUILD_CORE.
+ *
+ * On Windows, Py_BUILD_CORE_MODULE exports "PyInit_xxx" symbol, whereas
+ * Py_BUILD_CORE_BUILTIN does not.
+ */
+#if defined(Py_BUILD_CORE_BUILTIN) && !defined(Py_BUILD_CORE)
+#  define Py_BUILD_CORE
+#endif
+#if defined(Py_BUILD_CORE_MODULE) && !defined(Py_BUILD_CORE)
+#  define Py_BUILD_CORE
+#endif
+
+
 /**************************************************************************
 Symbols and macros to supply platform-independent interfaces to basic
 C language & library operations whose spellings vary across platforms.
@@ -623,7 +644,7 @@
 /* only get special linkage if built as shared or platform is Cygwin */
 #if defined(Py_ENABLE_SHARED) || defined(__CYGWIN__)
 #       if defined(HAVE_DECLSPEC_DLL)
-#               if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
+#               if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 #                       define PyAPI_FUNC(RTYPE) __declspec(dllexport) RTYPE
 #                       define PyAPI_DATA(RTYPE) extern __declspec(dllexport) RTYPE
         /* module init functions inside the core need no external linkage */
@@ -755,7 +776,7 @@
 #define PY_LITTLE_ENDIAN 1
 #endif
 
-#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN)
+#ifdef Py_BUILD_CORE
 /*
  * Macros to protect CRT calls against instant termination when passed an
  * invalid parameter (issue23524).