wrap make_flags() into fmt_flags() which returns a (struct-wrapped)
string, so the calls can be inlined into the printf statements, without
reserving buffers.
we locally force optimization, so copy elision is always done, as debug
builds would otherwise suffer a somewhat unreasonable performance hit.
this moves the channel iteration & synchronization code from main(),
with all its dependencies.
then it is "re-threaded" to be more directly driven by the driver
callbacks (like sync_boxes() is), rather than being a weird state
machine.
while the code is moved, localize many variables, and use an enum
instead of #defines for the states.
while at it, add/fix some licenses/copyrights/comments:
- it makes no sense to have a GPL exception in scripts
- ted did not contribute to the man page
- tst_timers is not part of the mbsync executable
- explicitly put the build system under GPL and add copyrights
... by making a lot of objects unsigned, and some signed.
casts which lose precision and change the sign in one go (ssize_t and
time_t to uint on LP64) are made explicit as well.
turns out that some IMAP servers (e.g., poczta.o2.pl) do not return
messages in ascending UID order in response to a UID FETCH request,
which makes the driver violate the API contract.
counter this by sorting the messages. this also addresses the
long-standing (but hypothetical) issue that parallel UID FETCH requests
could be handled out-of-order and thus also lead to mixed up results.
based on patch by Marcin Niestroj <macius1990w@gmail.com>.
