Split out Ruby to another repository / Tebako image

[ronaldtse]

We should split out the Ruby that is compiled for Tebako usage into a separate repository. And we should have it pre-built so people who use Tebako can just "download the appropriate compiled Ruby archive" and incorporate into their Tebako image.

[maxirmx]

It works the opposite way. Tebako image is incorporated into Ruby binary.
So it is not possible to 'download Ruby', you have to build it during packaging.

[maxirmx]

We have tebako ruby that is patched as follows:

1. Calls to certain OS io functions are replaced with calls to libdwarfs. Using c #define directives
2. In main function command line parameters are adjusted so that Ruby 'thinks' that it has been called to execute tebako-packaged application entry point script
3. Ruby build scripts are adjusted to refer to libdwarfs and to include cpp file that embeds tebako image
4. Ruby build scripts are adjusted to refer to as little shared libraries as possible

We have:

1. Tebako Ruby source code
2. Tebako Ruby build scripts
3. libdwarfs_wr, libdwarfs and a set of other libraries
4. Cpp file with embedded tebako image. I create a library out of it but it is just to simplify item 2.

The process then runs as follows:

• Ruby code is compiled on tebako setup
• On tebako press just a couple of files are compiled. However, if I link Ruby binary, build script executes full setup sequence for all native extensions. It implies complex bootstrap procedure that includes linking libruby.a, linking miniruby, extension configuration and rebuild, linking ruby, extension setup, linking ruby once again. This is the way ruby build script works.