buildroot

gcc: add patches to fix PR70473

gcc 5.x introduced a regression in the ARM build, which causes the
s-automata program to consume a very significant amount of RAM during
the gcc build. This causes numerous failures with our Travis-CI based
testing of defconfigs.

In order to address this, this commit backports a commit from the gcc
master branch, to both our gcc 5.x and gcc 6.x support.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>