make mercurial look in more places for config files.
now it searches <install dir>/etc/mercurial, /etc/mercurial, and user
hgrc.
this allows site-wide configuration to be shared over automounted nfs
partition, instead of chenging on every system. option of having local
configuration on every system remains.
old code for searching /etc/mercurial/hgrc.d never worked, this code
is tested and works.
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/