add _dbus_geteuid to fix EXTERNAL authentication in setuid applications

add _dbus_geteuid to fix EXTERNAL authentication in setuid applications

2008-01-14  John (J5) Palmieri  <johnp@redhat.com>

	* Patch by Andrea Luzzardi  <scox at sig11 dot org>: creates a
	_dbus_geteuid function to fix EXTERNAL authentication in setuid
	applications

	*  dbus/dbus-sysdeps-unix.c (_dbus_geteuid): used to get the effective
	uid of the running program
	(_dbus_credentials_add_from_current_process): use geteuid instead of
	getuid
	(_dbus_append_user_from_current_process): use geteuid instead of
	getuid

	* dbus/dbus-sysdeps-util-unix.c (_dbus_change_to_daemon_user): use
	geteuid instead of getuid
	(_dbus_unix_user_is_at_console): use geteuid instead of getuid

	* dbus/dbus-sysdeps-win.c (_dbus_geteuid): add a windows equivilant
	that returns DBUS_UID_UNSET