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/shamodule.c b/Modules/shamodule.c
index 0504fad..d56e90e 100644
--- a/Modules/shamodule.c
+++ b/Modules/shamodule.c
@@ -380,7 +380,7 @@
 static SHAobject *
 newSHAobject()
 {
-	return (SHAobject *)PyObject_NEW(SHAobject, &SHAtype);
+	return (SHAobject *)PyObject_New(SHAobject, &SHAtype);
 }
 
 /* Internal methods for a hashing object */
@@ -389,7 +389,7 @@
 SHA_dealloc(ptr)
 	PyObject *ptr;
 {
-	PyMem_DEL(ptr);
+	PyObject_Del(ptr);
 }