re2 is built with rebar and we do expect
rebar to be in the search PATH. If rebar can not be found in the search
PATH, it will be automatically downloaded to support/rebar for local use.
To build, execute make or rebar compile.
If re2 is found on the system, it will be used. Otherwise, the
re2 dependency is automatically downloaded to
c_src/re2 by the build script. If you prefer to link against re2 as found on
the system, you can set the env var SYSTEM_RE2. If you set SYSTEM_RE2 and
the library can not be found, it will fall back to a local copy, as if you
didn't use the env var. If you want to override the re2 version that is fetched
and built, when not using system re2, you can do so by setting RE2_REV to a
git rev.
Unless otherwise noted, the re2 source files
are distributed under the BSD-style license found in c_src/re2/LICENSE.