You are right! :) A make clean in the root of my local workspace solved
the problem but revealed another problem:

$ make
running build
running build_ext
building '_struct' extension
gcc -pthread -fPIC -fno-strict-aliasing -g -Wall -Wstrict-prototypes -I.
-I/home/heimes/dev/python/py3k/debug/./Include -I./Include -IInclude -I.
-I/usr/local/include -I/usr/local/include/python3.0 -c _struct.c -o
build/temp.linux-i686-3.0/_struct.o
gcc: _struct.c: No such file or directory
gcc: keine Eingabedateien
error: /home/heimes/dev/python/py3k/debug/Modules/_ctypes/libffi: No
such file or directory

I fixed the problem by adding the option -b $(srcdir) to setup.py build
in the Makefile.

Next I run into a problem with the modules. Apparently itertools was not
added as a built-in module.

running build
Traceback (most recent call last):
  File "../setup.py", line 1584, in <module>
    main()
  File "../setup.py", line 1579, in main
    'Lib/smtpd.py']
  File "/home/heimes/dev/python/py3k/Lib/distutils/core.py", line 148,
in setup
    dist.run_commands()
  File "/home/heimes/dev/python/py3k/Lib/distutils/dist.py", line 942,
in run_commands
    self.run_command(cmd)
  File "/home/heimes/dev/python/py3k/Lib/distutils/dist.py", line 960,
in run_command
    cmd_obj = self.get_command_obj(command)
  File "/home/heimes/dev/python/py3k/Lib/distutils/dist.py", line 847,
in get_command_obj
    self._set_command_options(cmd_obj, options)
  File "/home/heimes/dev/python/py3k/Lib/distutils/dist.py", line 868,
in _set_command_options
    bool_opts = map(translate_longopt, command_obj.boolean_options)
ImportError: /usr/local/lib/python3.0/site-packages/itertools.so:
undefined symbol: PyUnicodeUCS4_FromFormat

I copied $(srcdir)/Modules/Setup* ./Modules/ and Python compiled
itertools as built-ins.