Revert of [build] Use sysroot for linux compilation with clang (patchset #5 id:80001 of https://codereview.chromium.org/2028623002/ )

Reason for revert:
sysroot logic breaks "make arm"

Original issue's description:
> [build] Use sysroot for linux compilation with clang
>
> This ports the configuration for using a sysroot from
> chromium's common.gypi.
>
> This is restricted to clang only.
>
> BUG=chromium:474921, chromium:616032
> LOG=y
>
> Committed: https://crrev.com/c47d3c63695d2999752f5fc61ff171f3ff100553
> Cr-Commit-Position: refs/heads/master@{#36729}

TBR=jochen@chromium.org,vogelheim@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=chromium:474921, chromium:616032

Review-Url: https://codereview.chromium.org/2042693003
Cr-Commit-Position: refs/heads/master@{#36741}