If I clone ns-3-dev and run ./waf without running ./waf configure, I get the following python backtrace:

[mlacage@diese code]$ hg clone ssh://code@code.nsnam.org/repos/ns-3-dev
destination directory: ns-3-dev
requesting all changes
adding changesets
adding manifests
adding file changes
added 4098 changesets with 14692 changes to 1629 files
updating working directory
793 files updated, 0 files merged, 0 files removed, 0 files unresolved
[mlacage@diese code]$ cd ns-3-dev
[mlacage@diese ns-3-dev]$ ./waf
Reconfiguring the project
Checking for program g++                 : ok /usr/lib/ccache/g++ 
Checking for compiler version            : ok 4.3.2 
Checking for program cpp                 : ok /usr/bin/cpp 
Checking for program ar                  : ok /usr/bin/ar 
Checking for program ranlib              : ok /usr/bin/ranlib 
Checking for g++                         : ok  
Checking for program pkg-config          : ok /usr/bin/pkg-config 
Checking for -Wno-error=deprecated-declarations support : yes 
Checking for header stdlib.h                            : ok 
Checking for header signal.h                            : ok 
Checking for library rt                                 : ok 
Checking for header pthread.h                           : ok 
Checking for high precision time implementation         : 128-bit integer 
Checking for header stdint.h                            : ok 
Checking for header inttypes.h                          : ok 
Checking for header sys/inttypes.h                      : not found 
Checking for header linux/if_ether.h                    : ok 
Checking for pkg-config flags for GTK_CONFIG_STORE      : ok  
Checking for library sqlite3                            : ok 
Package goocanvas was not found in the pkg-config search path.
Perhaps you should add the directory containing `goocanvas.pc'
to the PKG_CONFIG_PATH environment variable
No package 'goocanvas' found
Checking for pkg-config flags for MOBILITY_VISUALIZER   : not found 
Checking for program python                             : ok /usr/bin/python 
Traceback (most recent call last):
  File "./waf", line 127, in <module>
    Scripting.prepare(t, cwd, VERSION, wafdir)
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Scripting.py", line 122, in prepare
    prepare_impl(t,cwd,ver,wafdir)
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Scripting.py", line 115, in prepare_impl
    main()
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Scripting.py", line 143, in main
    configure()
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Scripting.py", line 40, in configure
    conf.sub_config('')
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Configure.py", line 77, in sub_config
    ret=mod.configure(self)
  File "/home/mlacage/code/ns-3-dev/wscript", line 235, in configure
    conf.sub_config('bindings/python')
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Configure.py", line 77, in sub_config
    ret=mod.configure(self)
  File "/home/mlacage/code/ns-3-dev/bindings/python/wscript", line 130, in configure
    conf.check_python_version((2,3))
  File "/home/mlacage/code/ns-3-dev/.waf-1.5.2-e69116b0d3441cd20aea90dfddba6efd/wafadmin/Tools/python.py", line 241, in check_python_version
    python_LIBDEST=os.path.join(conf.env['PREFIX'],"lib","python"+pyver)
  File "/usr/lib/python2.5/posixpath.py", line 62, in join
    elif path == '' or path.endswith('/'):
AttributeError: 'list' object has no attribute 'endswith'

This is a bit unfriendly.