gn: use bundled binutils via -B

gn: use bundled binutils via -B

- Use bundled binutils by adding to cflags -B
- Enables dwarf-fission based on bundling (maybe correct?)
- Makes differ normalize -B paths so they can be compared between gyp/gn.

R=brettw@chromium.org
BUG=335824
Committed: https://crrev.com/416440522fa2e5034c76a2adbe069bc7c6faaf55
Cr-Commit-Position: refs/heads/master@{#295185}

[scottmg, 2014-09-16 22:56:39]

i think this makes sense now

[brettw, 2014-09-16 23:13:03]

lgtm

[scottmg, 2014-09-16 23:13:37]

The CQ bit was checked by scottmg@chromium.org

[commit-bot: I haz the power, 2014-09-16 23:14:58]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/568613002/40001

[commit-bot: I haz the power, 2014-09-17 00:19:41]

Committed patchset #3 (id:40001) as 2a01fb867ac475377220e660309d78ea922472aa

[commit-bot: I haz the power, 2014-09-17 00:20:25]

Patchset 3 (id:??) landed as
https://crrev.com/416440522fa2e5034c76a2adbe069bc7c6faaf55
Cr-Commit-Position: refs/heads/master@{#295185}