[PATCH] Hal privilige seperation

[Artem Kachitchkine]

> Also we probably only want to accept
> connections from uid 0 as an extra check just in case someone guesses
> the address..

This is especially important for OSes without abstract sockets - which 
is pretty much OS except Linux - where HAL's p2p sockets will actually 
appear in /tmp.

A more portable and secure way to maintain private connections would be 
socketpair(), passing descriptors through fork inheritance. One of these 
days I'll think about adding this to D-BUS.

-Artem.