Add the log-formats `multiline` and `multiline-with-logs` which offer
multiple current active building status lines.
Change-Id: Idd8afe62f8591b5d8b70e258c5cefa09be4cab03
This was caused by -L calling setLogFormat() again, which caused the
creation of a new progress bar without destroying the old one. So we
had two progress bars clobbering each other.
We should change 'logger' to be a smart pointer, but I'll do that in a
future PR.
Fixes#6931.
Needed so that we can include it as a logger in loggers.cc without
adding a dependency on nix
This also requires moving names.hh to libutil to prevent a circular
dependency between libmain and libexpr
Alois Wohlschlager