Revert of build: Remove build system support for gold plugin.

Revert of build: Remove build system support for gold plugin. (patchset #2 id:20001 of https://codereview.chromium.org/2891513002/ )

Reason for revert:
Broke CFI buildbots:

https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20CF
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20ToT

Need build file fixes to make is_cfi imply use_lld.

Original issue's description:
> build: Remove build system support for gold plugin.
> 
> R=thakis@chromium.org
> TBR=mseaborn@chromium.org
> BUG=607968
> 
> Review-Url: https://codereview.chromium.org/2891513002
> Cr-Commit-Position: refs/heads/master@{#472258}
> Committed: https://chromium.googlesource.com/chromium/src/+/5d98fe2426808ddc4c9526a49ce63db2ace279c2

TBR=thakis@chromium.org,mseaborn@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=607968
Review-Url: https://codereview.chromium.org/2892643002
Cr-Commit-Position: refs/heads/master@{#472516}
Committed: https://chromium.googlesource.com/chromium/src/+/76561105b5060a8fcfe39463eddbc60a3f776fb5

[pcc1, 2017-05-17 18:58:05]

The CQ bit was checked by pcc@chromium.org

[pcc1, 2017-05-17 18:58:05]

Created Revert of build: Remove build system support for gold plugin.

[commit-bot: I haz the power, 2017-05-17 18:59:55]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-17 19:00:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1495047485052650, "parent_rev":
"5c0ee4a90474214ea2dbd240e267a7b3f1e3fac3", "commit_rev":
"76561105b5060a8fcfe39463eddbc60a3f776fb5"}

[commit-bot: I haz the power, 2017-05-17 19:00:44]

Description was changed from

==========
Revert of build: Remove build system support for gold plugin. (patchset #2
id:20001 of https://codereview.chromium.org/2891513002/ )

Reason for revert:
Broke CFI buildbots:

https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20CF
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20ToT

Need build file fixes to make is_cfi imply use_lld.

Original issue's description:
> build: Remove build system support for gold plugin.
> 
> R=thakis@chromium.org
> TBR=mseaborn@chromium.org
> BUG=607968
> 
> Review-Url: https://codereview.chromium.org/2891513002
> Cr-Commit-Position: refs/heads/master@{#472258}
> Committed:
https://chromium.googlesource.com/chromium/src/+/5d98fe2426808ddc4c9526a49ce6...

TBR=thakis@chromium.org,mseaborn@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=607968
==========

to

==========
Revert of build: Remove build system support for gold plugin. (patchset #2
id:20001 of https://codereview.chromium.org/2891513002/ )

Reason for revert:
Broke CFI buildbots:

https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20CF
https://build.chromium.org/p/chromium.fyi/builders/CFI%20Linux%20ToT

Need build file fixes to make is_cfi imply use_lld.

Original issue's description:
> build: Remove build system support for gold plugin.
> 
> R=thakis@chromium.org
> TBR=mseaborn@chromium.org
> BUG=607968
> 
> Review-Url: https://codereview.chromium.org/2891513002
> Cr-Commit-Position: refs/heads/master@{#472258}
> Committed:
https://chromium.googlesource.com/chromium/src/+/5d98fe2426808ddc4c9526a49ce6...

TBR=thakis@chromium.org,mseaborn@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=607968

Review-Url: https://codereview.chromium.org/2892643002
Cr-Commit-Position: refs/heads/master@{#472516}
Committed:
https://chromium.googlesource.com/chromium/src/+/76561105b5060a8fcfe39463eddb...
==========

[commit-bot: I haz the power, 2017-05-17 19:00:44]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/76561105b5060a8fcfe39463eddb...