dbf9d6b48e
aRts development stopped in 2004, it's unlikely ever is still using it. Besides, these elements were never even ported to 0.10.
All aclocal .m4 files we need are put here and cat'd to acinclude.m4 in the source root. Official ones (taken from the relevant devel packages) are named as-is, unofficial ones (or changed ones) get a gst-prefix.