2.0.0.beta1: vendor RE2, native gems

Thanks to @stanhu: this is the first beta release of a major new version of re2 which no longer requires the RE2 library to be installed as it is now vendored with the gem (ala Nokogiri and libxml2).

Installing the gem will also compile and install RE2 (and its dependency, abseil). As this can take some time, precompiled native gems are available for major platforms meaning there’s no need to wait for compilation.

Due to a new dependency on MiniPortile2 and the need to include compiled C extensions for every supported version of Ruby in the native gems, this major version drops support for all Ruby versions prior to 2.7, matching Nokogiri’s policy of supporting the last 4 minor versions of Ruby (2.7, 3.0, 3.1 and 3.2).

To opt out of using the gem’s vendored dependencies and instead rely on the previous behaviour of linking against a system install of RE2, use the --enable-system-libraries option when installing the gem (note you’ll need to use the ruby platform to avoid the native gems too).

Known issues

• Installing and compiling the ruby platform gem (i.e. not one of the precompiled native gems) with the bundled dependencies on a system which has its own RE2 library installed in Ruby’s default exec_path will link incorrectly, see #93