I'm sorry that -j1 did not work for you, but this seems to fail every time if you try in a single-CPU machine.
You can see it fail in real time here: https://jenkins-1.reliable-builds.org/job/gcc-8-cross/ If trying in a single-CPU machine is a burden for you, please contact me privately and I will gladly provide full access to a single-CPU machine. (Same offer for Helmut in case he wants to confirm that this bug is indeed real and not the result of a misconfiguration on my side). Thanks.