Add command line arguments:
--import-proc-cmdline: import values from /proc/cmdline
--merge: import current values
--replace=ARG=VALUE: replace value
--append=ARG=VALUE: append a new argument
Extra command line arguments are treated like --append=, which
gives backwards compatibility.
https://bugzilla.gnome.org/show_bug.cgi?id=731051
Owen W. Taylor
262cba09c0