Bundle libc++ headers with clang.

Bundle libc++ headers with clang.

That way, -stdlib=libc++ works better, at least on OS X.

BUG=371034
TEST=`echo '#include <vector>" > test.cc ; bin/clang -c test.cc -stdlib=libc++ -isysroot $(xcrun -show-sdk-path)`
no longer complains about not finding the vector header on OS X.
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=270095

[Nico, 2014-05-13 12:08:22]

Two options:
1.) Add a "make install" for the non-bootstrap build and copy the headers from
there
2.) Bootstrap already does a "make install", and the libc++ headers are
identical between bootstrap and regular build, so just copy those (package.sh
always does a bootstrap build)

Patch set 1 does 1, patch set 2 does 2. 1 seems a bit clearer, 2 is shorter and
just as good in practice. I favor 2 a bit.

[hans, 2014-05-13 14:50:34]

On 2014/05/13 12:08:22, Nico (traveling this week) wrote:
> Two options:
> 1.) Add a "make install" for the non-bootstrap build and copy the headers from
> there
> 2.) Bootstrap already does a "make install", and the libc++ headers are
> identical between bootstrap and regular build, so just copy those (package.sh
> always does a bootstrap build)
> 
> Patch set 1 does 1, patch set 2 does 2. 1 seems a bit clearer, 2 is shorter
and
> just as good in practice. I favor 2 a bit.

Since this is in package.sh, which means we always do a bootstrap build, I think
2 is fine.

lgtm

[Nico, 2014-05-13 14:56:12]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2014-05-13 14:56:37]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/thakis@chromium.org/281753002/20001

[commit-bot: I haz the power, 2014-05-13 14:58:24]

Change committed as 270095

[Nico, 2014-08-05 18:18:38]

On 2014/05/13 12:08:22, Nico (away) wrote:
> Two options:
> 1.) Add a "make install" for the non-bootstrap build and copy the headers from
> there
> 2.) Bootstrap already does a "make install", and the libc++ headers are
> identical between bootstrap and regular build, so just copy those (package.sh
> always does a bootstrap build)
> 
> Patch set 1 does 1, patch set 2 does 2. 1 seems a bit clearer, 2 is shorter
and
> just as good in practice. I favor 2 a bit.

Since I had forgotten that I've done this already, I came up with a 3rd way when
I accidentally reimplemented this today: Like 1, but use libc++'s
"installheaders" target to only install the libc++ headers:
https://codereview.chromium.org/440143003/

If 2. isn't enough at some point, we can switch to that. Seems better than 1.