There are scenarios when it is necessary to globally redefine
a log macro. The existing logging frontend is not sufficient since
it redirects at the function level.
One example is using pigweed_tokenzier. The pigweed tokenizer depends
on intercepting log strings at the macro level to function.
Introduce an option to include a custom application provided header
named "zephyr_custom_log.h" at the end of log.h. This allows an
application to extend the LOG_* macros globally.
This change includes a simple test that redefines the core LOG macros
to include a custom prefix.
Signed-off-by: Rob Barnes <robbarnes@google.com>
61b5566e74