Add entries for the weakref module to the build control.

Modules/Setup.dist

@@ -147,6 +147,7 @@ GLHACK=-Dclear=__GLclear
 #struct structmodule.c	# binary structure packing/unpacking
 #time timemodule.c # -lm # time operations and variables
 #operator operator.c	# operator.add() and similar goodies
+#_weakref _weakref.c	# basic weak reference support
 #_codecs _codecsmodule.c	# access to the builtin codecs and codec registry
 
 #unicodedata unicodedata.c unicodedatabase.c

setup.py

@@ -153,6 +153,7 @@ class PyBuildExt(build_ext):
         exts.append( Extension('regex', ['regexmodule.c', 'regexpr.c']) )
         exts.append( Extension('pcre', ['pcremodule.c', 'pypcre.c']) )
 
+        exts.append( Extension('_weakref', ['_weakref.c']) )
         exts.append( Extension('xreadlines', ['xreadlinesmodule.c']) )
 
         # array objects