Implementation of per-user .hgignore.
Reference: http://www.selenic.com/mercurial/bts/issue166
If the [ui] section of .hgrc contains keys like "ignore" or
"ignore.something", the values corresponding to these keys are
treated as per-user hgignore files. These hgignore files apply to all
repositories used by that user.
syntax: glob
*.elc
*.orig
*.rej
*~
*.so
*.pyc
*.swp
*.prof
tests/*.err
build
dist
doc/*.[0-9]
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py
syntax: regexp
^\.pc/