Vladimir Marangozov's long-awaited malloc restructuring.
For more comments, read the patches@python.org archives.
For documentation read the comments in mymalloc.h and objimpl.h.

(This is not exactly what Vladimir posted to the patches list; I've
made a few changes, and Vladimir sent me a fix in private email for a
problem that only occurs in debug mode.  I'm also holding back on his
change to main.c, which seems unnecessary to me.)
diff --git a/Modules/cdmodule.c b/Modules/cdmodule.c
index 1b414c1..4a04e43 100644
--- a/Modules/cdmodule.c
+++ b/Modules/cdmodule.c
@@ -447,7 +447,7 @@
 {
 	if (self->ob_cdplayer != NULL)
 		CDclose(self->ob_cdplayer);
-	PyMem_DEL(self);
+	PyObject_Del(self);
 }
 
 static PyObject *
@@ -483,7 +483,7 @@
 {
 	cdplayerobject *p;
 
-	p = PyObject_NEW(cdplayerobject, &CdPlayertype);
+	p = PyObject_New(cdplayerobject, &CdPlayertype);
 	if (p == NULL)
 		return NULL;
 	p->ob_cdplayer = cdp;
@@ -761,7 +761,7 @@
 		self->ob_cdcallbacks[i].ob_cdcallbackarg = NULL;
 	}
 	CDdeleteparser(self->ob_cdparser);
-	PyMem_DEL(self);
+	PyObject_Del(self);
 }
 
 static PyObject *
@@ -799,7 +799,7 @@
 	cdparserobject *p;
 	int i;
 
-	p = PyObject_NEW(cdparserobject, &CdParsertype);
+	p = PyObject_New(cdparserobject, &CdParsertype);
 	if (p == NULL)
 		return NULL;
 	p->ob_cdparser = cdp;