The one specified by mdoc is hard to read for non-native
speakers from countries which read the date day-first (like
Germany, Greece, North-Korea, Swamp,...).
This is also consistent with how we generally specify dates
at suckless.org.
1) Properly document e, f and m-flags in the manpage.
2) Clear up the code for the m-flag-handling. Add idiomatic
'/'-path-traversal as already seen in mkdir(1).
3) Unwrap the SWAP_BUF()-macro.
4) BUGFIX: Actually handle the f-flag properly. Only resolve
the dirname and append the basename later.
5) Use fputs() instead of printf("%s", ...).
