Implement arflags in the GN build.

Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of http://crrev.com/1896163003 with fix.

Committed: https://crrev.com/5404cdff57233dbad6e0b20afd547e445c57cd23
Cr-Commit-Position: refs/heads/master@{#390797}

[brettw, 2016-04-29 22:09:14]

Description was changed from

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Remove concurrent_links variable from gcc_toolchain which was unused.

BUG=598599
Reland of http://crrev.com/1909163002 with no changes (now that a GN binary push
to fix the bug has gone in) which was a reland of http://crrev.com/1896163003
with fix.
==========

to

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Remove concurrent_links variable from gcc_toolchain which was unused.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

[brettw, 2016-04-29 22:09:14]

brettw@chromium.org changed reviewers:
+ brucedawson@chromium.org

[brettw, 2016-04-29 22:10:41]

The OOM errors on Android debug bots were a result of too many concurrent links.
I remove the "unused" concurrent_links computation because the variable wasn't
used, but I forgot that this is actually a built-in getting inherited in the
toolchain definition.

I tweaked the code there to make it more obvious what's going on.

[brettw, 2016-04-29 22:11:00]

Description was changed from

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Remove concurrent_links variable from gcc_toolchain which was unused.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

to

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was
confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

[brettw, 2016-04-29 22:11:04]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2016-04-29 22:11:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1924203004/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1924203004/20001

[commit-bot: I haz the power, 2016-04-29 23:10:49]

Description was changed from

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was
confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

to

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was
confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

[commit-bot: I haz the power, 2016-04-29 23:10:49]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-04-30 17:29:59]

Patchset 2 (id:??) landed as
https://crrev.com/5404cdff57233dbad6e0b20afd547e445c57cd23
Cr-Commit-Position: refs/heads/master@{#390797}

[commit-bot: I haz the power, 2016-04-30 18:03:24]

Description was changed from

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was
confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.
==========

to

==========
Implement arflags in the GN build.

This flag was recently added in GN. This patch hooks it up to the toolchains
and moves some flags to use it that previously had to be hardcoded on the
tool command itself.

Clarifies usage of concurrent_links variable in gcc_toolchain which was
confusing.

TBR=brucedawson@chromium.org
BUG=598599
Reland of http://crrev.com/1909163002 with fixes which was a reland of
http://crrev.com/1896163003 with fix.

Committed: https://crrev.com/5404cdff57233dbad6e0b20afd547e445c57cd23
Cr-Commit-Position: refs/heads/master@{#390797}
==========