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/Objects/fileobject.c b/Objects/fileobject.c
index c8b083e..7e0979f 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -215,7 +215,7 @@
 	if (f->f_mode != NULL) {
 		Py_DECREF(f->f_mode);
 	}
-	free((char *)f);
+	PyObject_DEL(f);
 }
 
 static PyObject *