Experimental scanner: pass -b to re2c.

Experimental scanner: pass -b to re2c.

It seems to generate a bit faster scanner.

From re2c doc:

-b: Implies -s. Use bit vectors as well in the attempt to coax better code out
of the compiler. Most useful for specifications with more than a few
keywords (e.g. for most programming languages).

-s: Generate nested ifs for some switches. Many compilers need this assist to
generate better code.

BUG=
R=dcarney@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=17371

[dcarney, 2013-10-24 10:32:52]

lgtm

[marja, 2013-10-24 11:01:22]

Committed patchset #1 manually as r17371 (presubmit successful).