Martin von Zweigbergk <martinvonz@google.com> [Wed, 27 May 2015 13:22:48 -0700] rev 25579
match: don't remove '.' from _includeroots
This makes _includeroots more like _fileroots and gives visitdir() a
nice symmetry in the two.
I'm hoping to later combine the two (_fileroots and _includeroots),
and having them treated similarly should make that step easier to
follow.