compile.c (rb_iseq_build_from_ary): remove misc handling

iseq->local_size is calculated, too, along with stack_size and
param.size, meaning there is no need to blindly load values in
the misc hash passed to us.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48725 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
version.c: no exit in ruby_show_copyright

* include/ruby/ruby.h (ruby_show_copyright_to_die): for source
  code backward compatibility.

* ruby.c (process_options): return Qtrue to exit the process
  successfully.

* version.c (ruby_show_copyright): no longer exit.
backward.h: split

* include/ruby/backward.h: split backward compatibilities from
  ruby.h.