Rbuildignore and mercurial

I've changed to Mercurial for my working copies of survival for a number or resons not relevant to this post.  When I do R CMD check, I get some warnings
about certain files in the .hg directory with odd names.  I've added the following 2 lines to my .Rbuildignore file without effect
^\.hg$
^\.hg.*

I'm not a Perl user so perhaps I'm reading the help page wrong.  Any pointers?
This doesn't affect Rforge since I don't push any of those files up to there.

Terry T.