Merge branch 'pc/remove-warn' into maint

* pc/remove-warn:
Remove a redundant errno test in a usage of remove_path
Introduce remove_or_warn function
Implement the rmdir_or_warn function
Generalise the unlink_or_warn function

diff --cc builtin/apply.c
Simple merge

diff --cc git-compat-util.h
Simple merge

diff --cc merge-recursive.c
Simple merge

diff --cc unpack-trees.c
Simple merge

diff --cc wrapper.c
Simple merge