Bug#909406: [regression] GCC-8 failed to compile Julia on armhf while GCC-7 worked.

[Mo Zhou <lumin@debian.org>]

Package: gcc-8
Version: 8.2.0-7
Severity: important

This happend on our buildd and Ubuntu buildfarm, and I reproduced it in my
qemu-armhf chroot:

  qemu: Unsupported syscall: 385
  Invalid Thumb instruction at 0xff5ef780: 0xee4c, 0x000e
  
  signal (4): Illegal instruction
  in expression starting at no file:0
  unknown function (ip: 0xff5ef77f)
  true_main at ./ui/./ui/repl.c:103
  main at ./ui/./ui/repl.c:233
  __libc_start_main at /lib/arm-linux-gnueabihf/libc.so.6 (unknown line)
  _start at /home/lumin/packages/julia.pkg/julia/usr/bin/julia (unknown line)
  Allocations: 36838 (Pool: 36838; Big: 0); GC: 0
  qemu: uncaught target signal 4 (Illegal instruction) - core dumped
  Illegal instruction

Source to reproduce:
  https://salsa.debian.org/julia-team/julia
  - tag: debian/1.0.0-3

In order to reproduce the armhf build failure, just revert this commit
https://salsa.debian.org/julia-team/julia/commit/b89c05c87f27d23513cb3f90cd534f775daea289