I just tried with the gcc 7.2.0 cross compiler. It took 28 minutes to compile the file but it did finish. It took 5 times the ram and 30 times the time that it took to compile for amd64. It was not stuck, just doing a lot of work trying to optimize it seems.
Fixing the causes of the warnings has no impact on the compile time, which is not really surprising. -- Len Sorensen