Use the C extension on truffleruby

.github/workflows/truffleruby.yml

@@ -0,0 +1,25 @@
+name: truffleruby
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby: [ 'truffleruby-head' ]
+    steps:
+    - name: git config
+      run: |
+        git config --global core.autocrlf false
+        git config --global core.eol lf
+        git config --global advice.detachedHead 0
+    - uses: actions/checkout@master
+    - name: Set up Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: ${{ matrix.ruby }}
+    - name: Install dependencies
+      run: bundle install
+    - name: Run test
+      run: rake

Rakefile

@@ -11,7 +11,7 @@ Rake::TestTask.new(:test) do |t|
   t.test_files = FileList["test/**/test_*.rb"]
 end
 
-if RUBY_ENGINE == "ruby"
+if RUBY_ENGINE == "ruby" || RUBY_ENGINE == "truffleruby"
   require 'rake/extensiontask'
   Rake::ExtensionTask.new(name)
   task :test => :compile

ext/io/console/extconf.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: false
 require 'mkmf'
 
-ok = true if RUBY_ENGINE == "ruby"
+ok = true if RUBY_ENGINE == "ruby" || RUBY_ENGINE == "truffleruby"
 hdr = nil
 case
 when macro_defined?("_WIN32", "")

lib/io/console.rb

@@ -1,4 +1,4 @@
-if RUBY_ENGINE == 'ruby'
+if RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'truffleruby'
   require_relative 'console.so'
 else
   require_relative 'console/ffi/console'