Merge branch 'jc/merge-symlink-ours-theirs' into maint

"git merge -Xours/-Xtheirs" learned to use our/their version when
resolving a conflicting updates to a symbolic link.

* jc/merge-symlink-ours-theirs:
merge: teach -Xours/-Xtheirs to symbolic link merge

diff --cc merge-recursive.c
Simple merge