bpo-35081: Move Py_BUILD_CORE code to internal/mem.h (GH-10249)

* Add #include "internal/mem.h" to C files using
  _PyMem_SetDefaultAllocator().
* Include/internal/mem.h now requires Py_BUILD_CORE to be defined.

2 files changed, 12 insertions, 10 deletions

diff --git a/Include/internal/mem.h b/Include/internal/mem.h
index a731e30..4a41b77 100644
--- a/Include/internal/mem.h
+++ b/Include/internal/mem.h
@@ -4,6 +4,10 @@
 extern "C" {
 #endif
 
+#ifndef Py_BUILD_CORE
+#  error "Py_BUILD_CORE must be defined to include this header"
+#endif
+
 #include "objimpl.h"
 #include "pymem.h"
 
@@ -145,6 +149,14 @@ PyAPI_FUNC(void) _PyGC_Initialize(struct _gc_runtime_state *);
 
 #define _PyGC_generation0 _PyRuntime.gc.generation0
 
+
+/* Set the memory allocator of the specified domain to the default.
+   Save the old allocator into *old_alloc if it's non-NULL.
+   Return on success, or return -1 if the domain is unknown. */
+PyAPI_FUNC(int) _PyMem_SetDefaultAllocator(
+    PyMemAllocatorDomain domain,
+    PyMemAllocatorEx *old_alloc);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Include/pymem.h b/Include/pymem.h
index 19f0c8a..23457ad 100644
--- a/Include/pymem.h
+++ b/Include/pymem.h
@@ -198,16 +198,6 @@ PyAPI_FUNC(void) PyMem_SetAllocator(PyMemAllocatorDomain domain,
 PyAPI_FUNC(void) PyMem_SetupDebugHooks(void);
 #endif   /* Py_LIMITED_API */
 
-#ifdef Py_BUILD_CORE
-/* Set the memory allocator of the specified domain to the default.
-   Save the old allocator into *old_alloc if it's non-NULL.
-   Return on success, or return -1 if the domain is unknown. */
-PyAPI_FUNC(int) _PyMem_SetDefaultAllocator(
-    PyMemAllocatorDomain domain,
-    PyMemAllocatorEx *old_alloc);
-#endif
-
-
 /* bpo-35053: expose _Py_tracemalloc_config for performance:
    _Py_NewReference() needs an efficient check to test if tracemalloc is
    tracing.