bpo-35053: Add Include/tracemalloc.h (GH-10091)

* Modify object.h to ensure that pymem.h is included,
  to get _Py_tracemalloc_config variable.
* Move _PyTraceMalloc_XXX() functions to tracemalloc.h,
  they need PyObject type. Break circular dependency between pymem.h
  and object.h.

Include/tracemalloc.h

@@ -0,0 +1,42 @@
+#ifndef Py_TRACEMALLOC_H
+#define Py_TRACEMALLOC_H
+
+#ifndef Py_LIMITED_API
+/* Track an allocated memory block in the tracemalloc module.
+   Return 0 on success, return -1 on error (failed to allocate memory to store
+   the trace).
+
+   Return -2 if tracemalloc is disabled.
+
+   If memory block is already tracked, update the existing trace. */
+PyAPI_FUNC(int) PyTraceMalloc_Track(
+    unsigned int domain,
+    uintptr_t ptr,
+    size_t size);
+
+/* Update the Python traceback of an object.
+   This function can be used when a memory block is reused from a free list. */
+PyAPI_FUNC(int) _PyTraceMalloc_NewReference(PyObject *op);
+
+/* Untrack an allocated memory block in the tracemalloc module.
+   Do nothing if the block was not tracked.
+
+   Return -2 if tracemalloc is disabled, otherwise return 0. */
+PyAPI_FUNC(int) PyTraceMalloc_Untrack(
+    unsigned int domain,
+    uintptr_t ptr);
+
+/* Get the traceback where a memory block was allocated.
+
+   Return a tuple of (filename: str, lineno: int) tuples.
+
+   Return None if the tracemalloc module is disabled or if the memory block
+   is not tracked by tracemalloc.
+
+   Raise an exception and return NULL on error. */
+PyAPI_FUNC(PyObject*) _PyTraceMalloc_GetTraceback(
+    unsigned int domain,
+    uintptr_t ptr);
+#endif
+
+#endif /* !Py_TRACEMALLOC_H */