Enable x64 build of host toolset

Enable 64-bit build of host toolset

When building v8 mksnapshot host toolset as 64-bit, it requires icu to
be 64-bit also.

BUG=346626
R=jochen@chromium.org, jshin@chromium.org

Committed: 262949

[Yang Gu, 2014-03-26 10:05:53]

Not sure if changes to icu for Chromium can be reviewed here. If yes, please
have a look, it's for x64 build.

[Anton, 2014-03-26 18:58:43]

Adding +jochen who is hopefully more familiar with ICU.

[jochen (gone - plz use gerrit), 2014-03-27 14:31:02]

lgtm

[jungshik at Google, 2014-03-27 17:21:41]

LGTM

[Yang Gu, 2014-03-28 00:23:43]

The CQ bit was checked by yang.gu@intel.com

[Sergey Berezin, 2014-03-28 16:41:49]

On 2014/03/28 00:23:43, Yang Gu wrote:
> The CQ bit was checked by mailto:yang.gu@intel.com

The base URL is not recognized by the CQ. Please commit manually, or re-upload
the CL with a different base URL.

[Sergey Berezin, 2014-03-28 16:41:54]

The CQ bit was unchecked by sergeyberezin@chromium.org

[jungshik at Google, 2014-03-28 17:52:24]

On 2014/03/28 16:41:54, Sergey Berezin wrote:
> The CQ bit was unchecked by
https://mail.google.com/mail/?view=cm&fs=1&tf=1&to=sergeyberezin@chromium.org

@yang.gu : 

icu tree is not supported by CQ. This CL has to be committed by hand, after
which icu revision has to be rolled in src/DEPS. I can land it for you if you
want to.

[Yang Gu, 2014-03-31 01:29:32]

On 2014/03/28 17:52:24, Jungshik Shin wrote:
> On 2014/03/28 16:41:54, Sergey Berezin wrote:
> > The CQ bit was unchecked by
> https://mail.google.com/mail/?view=cm&fs=1&tf=1&to=sergeyberezin@chromium.org
> 
> @yang.gu : 
> 
> icu tree is not supported by CQ. This CL has to be committed by hand, after
> which icu revision has to be rolled in src/DEPS. I can land it for you if you
> want to.

We're enabling x64 Chromium build, and we need this patch. So please help me
land this manually, and I will submit the CL for src/DEPS. Thanks!

[Torne, 2014-04-01 15:13:40]

Can you also do the same for target_arch=arm64? The same change will be required
there for the same reason :)

[Yang Gu, 2014-04-02 02:20:48]

Added both arm64 and mipsel64, PTAL. Note that I changed the commit message
accordingly.

[jochen (gone - plz use gerrit), 2014-04-02 09:28:04]

still lgtm

[Torne, 2014-04-02 09:36:25]

Jungshik, can you go ahead and land this/roll ICU when you get a chance? Thanks!

[Torne, 2014-04-10 08:04:23]

Committed patchset #2 manually as r262949 (presubmit successful).