Add V8_ALIGNAS() and V8_ALIGNOF() and use that in lazy-instance.h.

Add V8_ALIGNAS() and V8_ALIGNOF() and use that in lazy-instance.h.

This renames the existing V8_ALIGNAS() to V8_ALIGNED(), and introduces
V8_ALIGNAS(type, alignment) which aligns according to the type and falls
back to aligning according to alignment.

Also use __attribute__((aligned(n))) instead of __attribute__((__aligned__(n))).

R=svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=16318

[Benedikt Meurer, 2013-08-26 09:35:59]

Reland with better handling for older GCCs and MSVC.

[Sven Panne, 2013-08-26 10:38:18]

lgtm

[Benedikt Meurer, 2013-08-26 11:18:40]

Committed patchset #1 manually as r16318 (presubmit successful).