Hi >(autoconf specific copyrights)
they have special exceptions to be relicensed under another license. So, if you don't account them specifically they will fall in the common package license. Somebody just don't care about them (I don't think it is source of reject by ftpmasters). I think mentioning them is worth the effort, but probably you can avoid it, even if it is appreciate when copyright is the most "open" wrt single files. G.
