sys.path not being correctly set up

[gsnedders]

Given the foo/bar.py with import subdir and an empty foo/subdir/__init__.py, running python foo/bar.py exits with no exceptions printed and with an exit code of zero, however python -m vmprof foo/bar.py throws ImportError:

Traceback (most recent call last):
  File "/opt/pypy/lib-python/2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/opt/pypy/lib-python/2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/mnt/home-extra/gsnedders/Documents/other-projects/csswg-testsuite-pypy-env/site-packages/vmprof/__main__.py", line 69, in <module>
    main()
  File "/mnt/home-extra/gsnedders/Documents/other-projects/csswg-testsuite-pypy-env/site-packages/vmprof/__main__.py", line 58, in main
    runpy.run_path(args.program, run_name='__main__')
  File "/opt/pypy/lib-python/2.7/runpy.py", line 240, in run_path
    return _run_module_code(code, init_globals, run_name, path_name)
  File "/opt/pypy/lib-python/2.7/runpy.py", line 82, in _run_module_code
    mod_name, mod_fname, mod_loader, pkg_name)
  File "/opt/pypy/lib-python/2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "foo/bar.py", line 1, in <module>
    import subdir
ImportError: No module named subdir

This seems to be down to sys.path[0] differing between the two (sys.path[1:] is equal): without vmprof, it's the path to ./foo; with vmprof, it's '').