agent: Make the S2K calibration time runtime configurabe.
* agent/protect.c (s2k_calibration_time): New file global var. (calibrate_s2k_count): Use it here. (get_calibrated_s2k_count): Replace function static var by ... (s2k_calibrated_count): new file global var. (set_s2k_calibration_time): New function. * agent/gpg-agent.c (oS2KCalibration): New const. (opts): New option --s2k-calibration. (parse_rereadable_options): Parse that option.
Note that using an unrelistic high value (like 60000) takes quite some
time for calibration.
- GnuPG-bug-id: T3399
- Signed-off-by: Werner Koch <wk@gnupg.org>