Use of an 'int' to represent a 'bool' value is confusing.  Just
because dbus made the mistake of cementing their 4-byte wire
format of dbus_bool_t into their API doesn't mean we have to
repeat the mistake.  With a little bit of finesse, we can
guarantee that we provide a large-enough value to the DBus
code, while still copying only the relevant one-byte bool
to the client code, and isolate the rest of our code base from
the DBus stupidity.

* src/util/virdbus.c (GET_NEXT_VAL): Add parameter.
(virDBusMessageIterDecode): Adjust all clients.
* src/util/virpolkit.c (virPolkitCheckAuth): Use nicer type.
* tests/virdbustest.c (testMessageSimple, testMessageStruct):
Test new behavior.
Signed-off-by: NEric Blake <eblake@redhat.com>

The commit 1b854c76 introduced a new function 'virPolkitCheckAuth' and
in the #else section when you don't have polkit all attributes should be
follwed by ATTRIBUTE_UNUSED.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>

Spawning the pkcheck program every time a permission check is
required is hugely expensive on CPU. The pkcheck program is just
a dumb wrapper for the DBus API, so rewrite the code to use the
DBus API directly. This also simplifies error handling a bit.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

There are now two places in libvirt which use polkit. Currently
they use pkexec, which is set to be replaced by direct DBus API
calls. Add a common API which they will both be able to use for
this purpose.

No tests are added at this time, since the impl will be gutted
in favour of a DBus API call shortly.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>