In a long printf call with many placeholders, it's hard to see which argument
belongs to which placeholder.
The long printf-like calls in the INFO and CLIENT commands are rewritten into
pairs of (format, argument). These pairs are then rewritten to a single call with
a long format string and a long list of arguments, using a macro called FMTARGS.
The file `fmtargs.h` is added to the repo.
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
