When I want to build Automake (current Git version) with a parallel make ("make -j12"):
I surmise this one was caused by the same random timing failures as your other reports, 66353 and 66354. A couple days ago we finally installed a patch (thanks Bogdan and Jacob) so that development automake should no longer require development autoconf in order to avoid these problems. I.e., dev automake now falls back to the previous one-second-timestamp behavior unless autom4te is known to be new enough (specifically, that it uses Time::HiRes). Please confirm if possible ... --thanks, karl.