Extend the logger to support coloring messages. The log level is
colorized with per-level colors, and the category with a fixed color.
This makes the log output more readable.
Coloring is enabled by default when logging to std::cerr, and can be
disabled by setting the LIBCAMERA_LOG_NO_COLOR environment variable.
When logging to a file with LIBCAMERA_LOG_FILE, coloring is disabled. It
can be enabled for file logging using the logSetFile() function.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>