The (((void *) &(arg)) == ((void *) (arg))) trick does not work
with clang, because clang does not accept it as a constant
expression and doesn't allow using it in static_assert.
I was not able to write a generic (any type) IS_ARRAY macro
compatible with static_assert, but here we only need to check for
arrays of chars and uint8_t-s.
Previously, Graphene used the notation "pipe:<uint32_t>" to emulate
pipes, socketpairs, and UNIX domain sockets. In particular, pipes
and socketpairs received random integer IDs, and sockets received
deterministic integer IDs. However, 32-bit randomly generated IDs
may collide quite often. Since pipe IDs/names should *not* repeat
(otherwise e.g. derived crypto keys will be reused), this commit
changes pipe IDs (pipeid) from uint32_t to char[96], and pipe IDs
(names) become 256-bit random sequences.
Michał Kowalczyk