Merge branch 'jn/config-ignore-inaccessible' into maint

A git daemon that starts as "root" and then drops privilege often
leaves $HOME set to that of the root user, which is unreadable by
the daemon process, which was diagnosed as a configuration error.

Make per-user configuration files that are inaccessible due to
EACCES as though these files do not exist to avoid this issue, as
the tightening which was originally meant as an additional security
has annoyed enough sysadmins.

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

diff --cc dir.c
Simple merge

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