In the previous commit I happened to notice a %.150s in a ppl_logevent
call, which was probably an important safety precaution a couple of
decades ago when that format string was being used for an sprintf into
a fixed-size buffer, but now it's just pointless cruft.
This commit removes all printf string formatting directives with a
compile-time fixed size, with the one exception of a %.3s used to cut
out a 3-letter month name in scpserver.c. In cases where the format
string in question was already going to an arbitrary-length function
like dupprintf or ppl_logevent, that's all I've done; in cases where
there was still a fixed-size buffer, I've replaced it with a dynamic
buffer and dupprintf.