Use iconv to ensure the output of calendar respects the output encoding

[bapt]

Summary

Use iconv to ensure the output of calendar respects the output encoding

Test Plan

tested with french and russian calendars

[jilles]

usr.bin/calendar/calendar.c

90–95 ↗

(On Diff #54008)

Perhaps nl_langinfo(CODESET) is better than hard-coding the locale name format.

usr.bin/calendar/events.c

83 ↗

(On Diff #54008)

Style: the open brace should be on a line by itself.

198 ↗

(On Diff #54008)

This strdup is unnecessary. The pointer can be saved instead and freed after the asprintf.

[bapt]

Address @jilles comments

[bapt]

Fix style