Create a parsing_ctx structure. This type is used to store information
about the current file/line parsed. A global context is created and
can be manipulated when haproxy is in STARTING mode. When starting is
over, the context is resetted and should not be accessed anymore.
Always print message in ha_alert/warning/notice when starting is over,
regardless of quiet/verbose options.
This change is useful to retrieve the output via the newly implemented
user messages buffer at runtime, for the CLI handlers.
The user messages buffer is used to store the stderr output after the
starting is over. Each thread has it own user messages buffer. Add some
functions to add a new message, retrieve and clear the content.
The user messages buffer primary goal is to be consulted by CLI
handlers. Each handlers using it must clear the buffer before starting
its operation.
Move functions related to errors output on stderr from log.c to a newly
created errors.c file. It targets print_message and
ha_alert/warning/notice/diag functions and related startup_logs feature.
