This PR introduces new debug macros that allow a more fined control of
which debug message to output and introduce C++ stream style for debug
messages.
Changing existing messages (except a few that I changed for testing)
will come in subsequent PRs.
I also think that we should make debug enabling OpenMP agnostic but, for
now, I prioritized maintaing the current libomptarget behavior for now,
and we might need more changes further down the line as we we decouple
libomptarget.
66ddc9b3e7