Revert "Stop using -std=gnu*"

This reverts commit c85c6c919698348c3aec13badd5f73e972040ff4.

Reason for revert: Broke AFL ASan builder
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Afl%20Upload%20Linux%20ASan

Original change's description:
> Stop using -std=gnu*
> 
> BUG=427584
> R=​thakis
> TBR=sbc
> 
> Change-Id: I4a6f67aa6ddaf8ab78719a3c925fcd732b8c28bf
> Reviewed-on: https://chromium-review.googlesource.com/1149337
> Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#581478}

TBR=thakis@chromium.org,thomasanderson@chromium.org

Change-Id: Ie673c185580662fad3d641000edfc4ee203acf9a
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 427584
Reviewed-on: https://chromium-review.googlesource.com/1166663
Reviewed-by: Abhishek Arya <inferno@chromium.org>
Commit-Queue: Abhishek Arya <inferno@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581481}
5 files changed