Revert 257618 "roll clang 198389:202554"

Revert 257618 "roll clang 198389:202554"

A bunch of mac builder bots are still on 10.6 (http://crbug.com/353529)          

> roll clang 198389:202554
> 
> This change contains several big changes, many of the caused by upstream
> llvm enabling c++11 in their codebase and thus having higher minimum
> requirements for their toolchain and runtime environment:
> 
> * clang on OS X now requires libc++, which means it'll only run on OS X 10.7+,
>   so change the deployment target from 10.5 to 10.7 (we were planning on
>   requiring 10.8 or 10.9, see bug 335325, but since several people are waiting
>   on a new clang, let's go to 10.7 only for now and do more as a follow-up)
> * On OS X, the compiler is only usable with libc++ if libc++ is checked out
>   and `make install` is run, so do that for the phase 1 compiler.
>   (Chrome doesn't use libc++ yet, so we don't do that for the bootstrapped
>   compiler.)
> * clang on linux now needs libstdc++ 4.7+ which isn't present on precise.
>   So we now include a newer libstdc++ in the compiler bundle (meaning
>   this clang should still run on precise).
> * clang is broken for android at r202554. To unblock oilpan, merge three
>   later changes into this roll, llvm r202793, r203601, and r203635
> 
> Regular, less tricky clang roll stuff:
> * Disable the new warning -Wabsolute-value for now (crbug.com/351479
>   for turning it on)
> * Disable -Wno-tautological-pointer-compare for libxml where it now
>   fires.
> * Since this bundles a new version of the oilpan plugin, bump its suffix to _3
> * Change plugin code to track upstream api change
> * Remove plugin flag check-url-directory as that's now always on
> 
> Due to the c++11 stuff, it's likely that this change will get reverted a few times.
> 
> BUG=351479, 287029, 341352, 333968, 335325
> TBR=hans@chromium.org
> 
> Review URL: https://codereview.chromium.org/195623002

TBR=thakis@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=257620

[Nico, 2014-03-18 11:57:15]

Committed patchset #1 manually as r257620 (tree was closed).