problems between Win32 (with its broken implementation) and the standard
stdio API. Also fixed a bug in debug output where long messages got
truncated to 1023 chars, and in xmpp_stanza_to_text where long stanzas
got truncated by one character.
Also prune the build spec for the examples. -Iexpat/lib will have to be
added again if we ever use expat in the example clients directly, but
for now it's unnecessary.
Having debugging on by default in the example seems to help
people trying out the library, and with the default_logger()
call it's not too much extra complication.
We should also write an example/complex.c that exercises
all the callback options, a custom allocator and so on.
