gprolog 1.4.4 and 1.4.5 run failure with gcc 8.2.0, success with clang 6.0.2 on FreeBSD.

I've filed a bug report at
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=231393

Summary: gprolog builds successfully however when run, it hangs and
consumes 100% of a CPU (this is run on a Xeon 8 logical cores).
Building with clang 6.0.2 with --disable-regs is successful on both i386
and amd64.

Both gprolog and gplc hangs indefinitely with gcc8.

(Unfortunately I'm a PROLOG person and have no idea how to dig deeper).
Sorry.