change default strftime format for better portability
On some systems, such as Solaris and HP-UX, "%c" format
give output without the leading zero on the single-digit
month-day.
port:4:export
port:4:vaportight
port:4:import/export
FIXME: history is wrong here
port:1:1:-:eggs:import
port:1:2:+:eggs:vaportight
port:1:3:+:eggs:import/export
port:0:2:+:spam:export
port:0:1:+:spam:import
port:4:import/export