Use clang by default for mips builds

Use clang by default for mips builds

This matches the current behavior or all the other
linux builds.

There seems to be single warning (from the
GNU assembler) in the entire build, but this also
occurs with gcc:
Warning: tried to set unrecognized symbol: oddspreg

TEST=GYP_DEFINES="target_arch=mipsel" GYP_CROSSCOMPILE=1 build/gyp_chromium && ninja -C out/Release

Committed: https://crrev.com/960a546bb897a909abf9d31f3d503923d62bfe73
Cr-Commit-Position: refs/heads/master@{#340991}

[Sam Clegg, 2015-07-27 20:56:27]

The CQ bit was checked by sbc@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-27 20:57:38]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1260803002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1260803002/1

[Sam Clegg, 2015-07-27 22:32:40]

sbc@chromium.org changed reviewers:
+ petarj@mips.com

[commit-bot: I haz the power, 2015-07-27 23:26:24]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-27 23:26:24]

Dry run: This issue passed the CQ dry run.

[petarj, 2015-07-28 23:53:31]

lgtm
Thanks.

[Sam Clegg, 2015-07-29 00:14:24]

The CQ bit was checked by sbc@chromium.org

[Sam Clegg, 2015-07-29 00:14:47]

sbc@chromium.org changed reviewers:
+ dpranke@chromium.org

[Sam Clegg, 2015-07-29 00:14:48]

+dpranke for build/OWNERS

[commit-bot: I haz the power, 2015-07-29 00:15:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1260803002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1260803002/1

[commit-bot: I haz the power, 2015-07-29 00:15:22]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-29 00:15:23]

No L-G-T-M from a valid reviewer yet. Only full committers are accepted.
Even if an L-G-T-M may have been provided, it was from a non-committer,
_not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[Dirk Pranke, 2015-07-29 00:27:24]

lgtm

[Sam Clegg, 2015-07-29 19:38:23]

The CQ bit was checked by sbc@chromium.org

[commit-bot: I haz the power, 2015-07-29 19:38:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1260803002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1260803002/1

[commit-bot: I haz the power, 2015-07-29 21:29:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-29 21:30:17]

Patchset 1 (id:??) landed as
https://crrev.com/960a546bb897a909abf9d31f3d503923d62bfe73
Cr-Commit-Position: refs/heads/master@{#340991}