-s is no longer needed, only the first non-option argument is
loaded (though you can use -- if the script name begins with a -).
main is then called automatically if defined. -u was changed to -m.
and non-mutated identifiers. helps a lot with the default
syntax-rules constructions - in particular reduces the number of
bytecode allocations for (chibi match) from 2397 to 1872.
can disable with USE_BIGNUMS=0 - the interactions between this and
USE_FLONUMS are messy, so they will likely be merged into a single
option in the near future (i.e. you either have only fixnums, or a
full range of numeric types).
adding rationals based on this would be easy and is a likely future
feature. adding native support for complex numbers is unlikely.
