log : make generating separate log files optional (#3787)
* impl --log-new, --log-append
* Update common/log.h
Co-authored-by: cebtenzzre <cebtenzzre@gmail.com>
* Update common/log.h
Co-authored-by: cebtenzzre <cebtenzzre@gmail.com>
* Apply suggestions from code review
Co-authored-by: cebtenzzre <cebtenzzre@gmail.com>
---------
Co-authored-by: cebtenzzre <cebtenzzre@gmail.com>