2) For 'install-info', what would be the replacement? Even though Automake knows how to handle its absence [1], it would be good to know.
On systems where install-info is lacking, we simply don't install a node entry in the dir file and continue with the post-install. This is a slightly different behaviour than what we have for other programs which we generally consider a hard error. E.g., if you don't have grep -E, and no egrep or some other such ... you're shit outta luck.