Applied suggested fix from Andrew Andrew <andrew@ugh.net.au> with
some stylistic changes. Thanks.
2. #include <sys/time.h> -> #include <time.h>
3. Removed #include <sys/param.h>
4. Use setlocale(3) and strftime(3) instead of ctime(3).
5. Clean up -Wall warnings.
6. Make sure, time to leave are integral minutes if the argument
is absolute. (i. e. without "+"). If started at 10:10:55 with
argument "1020" it computed time to leave as 10:20:55 instead of
10:20:00.
PR: 5395
