Move to C++ for debuggerd.

This is part 1, only including the bare minimum changes because
our diff tool doesn't easily show differences when a file moves. This
also breaks it into a small chunk in case some other changes break things,
as unlikely as I think that will be.

Change-Id: Ib7a3e7a2cc1ac574d15b65fda23813ebcf5d31af
9 files changed