https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797
--- Comment #9 from Jack Howarth <howarth.at.gcc at gmail dot com> --- (In reply to Francois-Xavier Coudert from comment #8) > Can reproduce with GNU Make 4.2.1, on the same system. I assume all of these builds are done using a gcc7.rb file run under ruby, correct? You might try a manual build outside of ruby (but duplicating there exact build approach). There is a history of certain race condition bugs only being exposed when make is run under a particular program... http://savannah.gnu.org/bugs/index.php?46261