re2: add dot_nl to the RE2::Options class

This allows clients to set the ā€œsā€ flag by default for a given
regular expression without the need to mess with the pattern by
prefixing it with ā€œ(?s)ā€.  This matters if the pattern comes
from the user.

Fixes issue 70.

R=rsc
CC=re2-dev
https://codereview.appspot.com/44070048
4 files changed