Re: [PATCHv2 4/8] ident: keep separate "explicit" flags for author and committer

Jeff King wrote:

  1. GIT_COMMITTER_* is set explicitly, but we fallback for
     GIT_AUTHOR. We claim the ident is explicit, even though
     the author is not.

  2. GIT_AUTHOR_* is set and we ask for author ident, but
     not committer ident. We will claim the ident is
     implicit, even though it is explicit.

This patch uses two variables instead of one, updates both
when we set the "fallback" values, and updates them
individually when we read from the environment.

Nice problem description.  The fixed behavior makes sense to me, for
what it's worth.

Not about this patch, but: in case (1), shouldn't the author fall
back to $GIT_COMMITER_NAME?