Now that the necessary functions from log.h have been moved to macro.h,
we can stop including log.h in macro.h. This requires modifying source
files all over the tree to include log.h instead.
In one of the next commits we'd like to introduce a concept of
optionally hashing the hostname from the machine ID. For that we we need
to optionally back gethostname_full() by code involving sd-id128, hence
let's move it from src/basic/ to src/shared/, since only there we are
allowed to use our public APIs.
In subsequent commits, calls to if_nametoindex() will be replaced by a wrapper
that falls back to alternative name resolution over netlink. netlink support
requires libsystemd (for sd-netlink), and we don't want to add any functions
that require netlink in basic/. So stuff that calls if_nametoindex() for user
supplied interface names, and everything that depends on that, needs to be
moved.