[Buildroot] [PATCH] gcc: bump 7.x series to 7.2.0

[Andrey Yurovsky]

Hi Thomas,

On Wed, Aug 16, 2017 at 1:30 PM, Thomas Petazzoni
<thomas.petazzoni at free-electrons.com> wrote:
> I'm not sure whether we want this for master or next. I've built 71
> toolchains with GCC 7.2.0 for toolchains.free-electrons.com, the vast
> majority of them being then used to build and boot a Linux kernel +
> minimal userspace under Qemu.
>
> Unfortunately, the tag gcc-7_2_0-release has still not appeared in
> git://gcc.gnu.org/git/gcc.git, so it's hard to see the amount of
> changes between gcc 7.1.0 and gcc 7.2.0.

I suspect this fixes real issues I've seen, including inability to
build systemd due to a GCC7 bug
(https://bugs.busybox.net/show_bug.cgi?id=10136) and some other GCC7
issues I've seen internally. I'll rebuild with this applied and verify
and then comment on the systemd build bug.