Merge branch 'jn/config-ignore-inaccessible'

When $HOME is misconfigured to point at an unreadable directory, we
used to complain and die. This loosens the check.

* jn/config-ignore-inaccessible:
config: allow inaccessible configuration under $HOME

diff --cc dir.c
Simple merge

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