Make `otPlatLogOutput()` `OT_TOOL_WEAK` in `cli_logging.cpp` so that
applications can provide their own strong definition to customize
instance-aware log output behaviour.
This commit provides the platform-level implementation for the
instance-aware logging API `otPlatLogOutput()`. This API is used when
`OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE` is enabled, allowing
the platform to receive the `otInstance` pointer with each log line.
The new API is implemented across:
- The simulation platform logging.
- The POSIX platform using `syslog()`.
- The NCP base to route logs to the NCP host.
- The CLI logging module.
- Unit tests and mock platforms.
The `OPENTHREAD_CONFIG_LOG_INSTANCE_AWARE_API_ENABLE` configuration is
also enabled for Toranj simulations to support multi-instance log
testing.
Refactors the example CLI app and the CLI module code to provide a
default implementation of the 'APP' log output option for any CLI
apps. This default is used when log output is configured to 'APP'
output and the CLI application itself does not provide its own
implementation of `otPlatLog()`.
This extends the current logging option (syslog) for the Posix app
ot-cli with the option to direct the log output to the CLI app, which
then prints it in stdout. This logging option can be enabled using the
existing -DOT_LOG_OUTPUT=APP. Previously, this gave a build error for
the Posix platform. This logging method is useful/required for running
NCPs in OTNS, such that the simulator can capture all log output and
at the same time syslog is not overly burdened on the host machine.
Suvesh Pratapa