Fix walkhelper on windows. The ''seen'' dictionary stores paths in canonical form, so the walkhelp must also provide paths in that form, otherwise the changed files are listed twice.

syntax: glob

*.elc
*.orig
*.rej
*~
*.so
*.pyc
*.swp
*.prof
tests/*.err
build
dist
doc/*.[0-9]
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py

syntax: regexp
^\.pc/