egghead we compile with same ruby version we use inside mobile app (2.3.4) so it should not be the reason. The ruby version shipped in Windows installer is only needed to run rake scripts ( and you don't have to install it if you already have new version - you can just install gems to your ruby. ) Please share your files - source, configuration etc. We'll reproduce it on our side.
Alex, I'm not sure I understand what you mean. No, I don't have Ruby 2.3.4 for build. If it was so, I expect it to build successfully. My Ruby version for build is coming from RMS, so 1.9.3 whereas the VM is 2.3.4. These 2 don't match. So solution is to upgrade the Ruby that comes with installer. Is that possible? If yes, when can we expect updated installer?
To reproduce, simply run installer in a Windows machine without any Ruby installed, create a simple extension, and compile. That error will show up.
I'm away from dev PC so cannot upload my source code, but I'm sure you can reproduce at your end with a clean install using installer.
Ruby compiled files, ISEQs, are made not with Ruby coming with RMS. We make it with separate RubyWin/RubyMac executable based on our own modified Ruby codebase, which is same as Ruby VM runing on device, currently 2.3.4.