MINOR: log: Try to get the status code when MUX_EXIT_STATUS is retrieved

The mux .ctl callback can provide some information about the mux to the
caller if the third parameter is provided. Thus, when MUX_EXIT_STATUS is
retrieved, a pointer on the status is now passed. The mux may fill it. It
will be pretty handy to provide custom error code from h1 mux instead of
default ones (400/408/500/501).
1 file changed