bus: update kdbus.h
src/core/selinux-access: #include <sys/socket.h>

Fixes the following build errors on Fedora 20:

  CC       src/core/libsystemd_core_la-selinux-access.lo
src/core/selinux-access.c: In function 'get_audit_data':
src/core/selinux-access.c:245:22: error: storage size of 'ucred' isn't known
         struct ucred ucred;
                      ^
src/core/selinux-access.c:259:9: warning: implicit declaration of function 'getsockopt' [-Wimplicit-function-declaration]
         r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len);
         ^
src/core/selinux-access.c:259:28: error: 'SOL_SOCKET' undeclared (first use in this function)
         r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len);
                            ^
src/core/selinux-access.c:259:28: note: each undeclared identifier is reported only once for each function it appears in
src/core/selinux-access.c:259:40: error: 'SO_PEERCRED' undeclared (first use in this function)
         r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &len);
                                        ^
src/core/selinux-access.c:245:22: warning: unused variable 'ucred' [-Wunused-variable]
         struct ucred ucred;
                      ^
make[2]: *** [src/core/libsystemd_core_la-selinux-access.lo] Error 1
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2
libsystemd-bus: bring definitions in sync with kdbus

In particular, KDBUS_ITEM_NEXT is now called KDBUS_PART_NEXT, and
KDBUS_ITEM_FOREACH was renamed to KDBUS_PART_FOREACH and takes one more
argument to make it more flexible.
libsystemd-bus: query minimum buffer size for KDBUS_CMD_NAME_QUERY

When starting in kernel mode, determine the minimum buffer size for
subsequent KDBUS_CMD_NAME_QUERY calls. The value returned by kdbus is
dependant on kernel config settings and may vary from system to system
and also in the future, but it is fix for a bus lifetime.
libsystemd-bus: add kdbus support for sd_bus_list_names()

kdbus will tell us the minimum buffer size it needs in case the default
8kb buffer doesn't suffice.
libsystemd-bus: add kdbus support for sd_bus_get_owner(|_pid|_uid)

Introduce kdbus_name_info as internal helper to make the actual ioctl()
to kdbus.
libsystemd-bus: add sd_bus_get_selinux_ctx() and sd_bus_get_audit_session_data()

Implementations for both org.freedesktop.DBus and kdbus are available
libsystemd-bus: gracefully handle 0-sized payload vectors

Such messages arise when 1:1-bridging legacy clients to kdbus.
libsystemd-bus: make sd_bus_list_names return all connections, including unique names
systemd-stdio-bridge: make it socket-activatable and usable as kdbus bridge

Augment systemd-stdio-bridge a bit to make it a 1:1 bridge from legacy
DBus clients to kdbus. In particular,

 * allow setting the bus path of the upstream bus as command line
   argument
 * use sd_listen_fds() for systemd's socket activation
 * omit calling sd_bus_negotiate_fds() when upstream bus is kdbus
 * reply to bus send errors with proper dbus error messages
 * treat -ECONNRESET as expected end-of-connection condition
dbus bridge service and socket files
dbus core service ... wip commit