* common/homedir.c (gnupg_socketdir): New.
* agent/gpg-agent.c (create_socket_name): Use new function instead of
gnupg_homedir.
(check_own_socket): Ditto.
(check_for_running_agent): Ditto.
* agent/preset-passphrase.c (main): Ditto.
* common/asshelp.c (start_new_gpg_agent): Ditto.
* scd/scdaemon.c (create_socket_name): Ditto.
* tools/gpgconf.c (main): Ditto.
* tools/symcryptrun.c (main): Ditto.