Exceptions aren't enough to debug complicated code paths like debug info
discovery or stack unwinding. We really need logs for that, so let's add
a small logging framework. By default, we log to stderr, but we also
provide a way to direct logs to a different file, or even an arbitrary
callback so that logs can be directed to the application's logging
library of choice.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
