part that does zic(8)/zdump(8) is still yet to be imported (but the old
zic and zdump will work just fine with these header files and the
data format has not changed).
changeover, so we have to extend the format of timezone files (in a backward-
compatible way, of course). This probably means that libc needs a minor
version number bump before 2.2 is released (or maybe not).
