some bash macros are missing from acinclude.m4 which are added up-stream. This
wasn't actually breaking anything but but it was causing the configure script
to not run all the tests it's intended to run.
move the acinclude.m4 from "files" folder to version specific folders so that
readline-5.2 continue to use the older acinclude.m4 only readline-6.2 use the
updated one
