We want the commit timestamps to be predictable (ie, to depend on the
source info only), so that we don't show spurious disagreement between
two working trees. So, use the timestamp of the HEAD commit.
git fetch --no-tags -p "$remote" \
+"HEAD:refs/remotes/$remote/HEAD"
cd $innerwd
+ GIT_AUTHOR_DATE=$(git log -n1 --pretty=format:'%ai')
+ GIT_COMMITTER_DATE=$GIT_AUTHOR_DATE
+ export GIT_COMMITTER_DATE GIT_AUTHOR_DATE
git checkout -b WORKTREE
gitfetchinfo_perhaps_commit INDEX
git add -Af .