gdb cannot run due to python error

I am trying to run gdb, but as soon as I hit enter I get this error

Traceback (most recent call last):
  File "/usr/lib/python2.7/site.py", line 562, in <module>
    main()
  File "/usr/lib/python2.7/site.py", line 544, in main
    known_paths = addusersitepackages(known_paths)
  File "/usr/lib/python2.7/site.py", line 271, in addusersitepackages
    user_site = getusersitepackages()
  File "/usr/lib/python2.7/site.py", line 246, in getusersitepackages
    user_base = getuserbase() # this will also set USER_BASE
  File "/usr/lib/python2.7/site.py", line 236, in getuserbase
    USER_BASE = get_config_var('userbase')
  File "/usr/lib/python2.7/sysconfig.py", line 577, in get_config_var
    return get_config_vars().get(name)
  File "/usr/lib/python2.7/sysconfig.py", line 476, in get_config_vars
    _init_posix(_CONFIG_VARS)
  File "/usr/lib/python2.7/sysconfig.py", line 337, in _init_posix
    makefile = _get_makefile_filename()
  File "/usr/lib/python2.7/sysconfig.py", line 331, in _get_makefile_filename
    return os.path.join(get_path('platstdlib').replace("/usr/local","/usr",1), "config" + (sys.pydebug and "_d" or ""), "Makefile")
AttributeError: 'module' object has no attribute 'pydebug'

am I missing some package? I have 12.04

Edit:

$ file /usr/bin/gdb
/usr/bin/gdb: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x8cd6c593fd6ffe6fd72266bf3d3407ea599b8143, stripped

$ dpkg -S /usr/bin/gdb
gdb: /usr/bin/gdb

See StackExchange question on this issue.

GDB uses python for scripting, but appears to have problems if you have built your own version of python. It finds your new python executable, but then tries to load the system python configuration, causing a mismatch. This seems to be a problem that applies more widely to other applications that embed python.

Quick and dirty work-around, export PYTHONPATH="" for just one session. Linked SE question unfortunately gives no long term solutions yet.