Giovanni Campagna authored Apr 21, 2013 and Philip Chimento committed Aug 01, 2020

Move handling of very special arguments (arrays, callback, caller
allocates) to the argcache virtual functions, and clean up
function invocations.
We now have three straight loops: marshal_in, marshal_out and
release. Some pointer arithmetics is introduced to ensure that
all indexes line up correctly.

(Philip Chimento: rebased and fixed coding style and bugs.)