The tracing crate is initialized with an optional log path, and will
either start a background thread for non-blocking log writing, or write
directly to standard output with ANSI encoding.
C preprocessor macros are used to emulate the Rust macros natively
provided by the tracing crate. They handle the creation of static
tracing callsites, and ensure that the correct file and line number
information is used for each logging site.
This enables IDE integration to work (which requires the Cargo.toml to
be in the repo root).
"make clean" no longer runs "cargo clean", because IDE integrations hold
locks on files within the Rust build directory, and an error inside
"cargo clean" error would prevent "make clean" from completing (and
removing other files).