Add libs.

.gitmodules

@@ -0,0 +1,12 @@
+[submodule "libs/mruby"]
+  ignore = dirty
+  path = libs/mruby
+  url = https://github.com/mruby/mruby.git
+[submodule "libs/mgems/mruby-marshal-c"]
+  ignore = dirty
+  path = libs/mgems/mruby-marshal-c
+  url = https://github.com/LanzaSchneider/mruby-marshal-c.git
+[submodule "libs/mgems/mruby-env"]
+  ignore = dirty
+  path = libs/mgems/mruby-env
+  url = https://github.com/iij/mruby-env.git

libs/changes.patch

@@ -0,0 +1,40 @@
+--- ./mruby/build_config/default.rb
++++ ./mruby/build_config/default.rb
+@@ -1,6 +1,18 @@
+ MRuby::Build.new do |conf|
+   # load specific toolchain settings
+-  conf.toolchain
++  conf.toolchain :gcc
++
++  conf.cc do |cc|
++    cc.command = ENV['CC']
++  end
++
++  conf.cxx do |cxx|
++    cxx.command = ENV['CXX']
++  end
++
++  conf.linker do |linker|
++    linker.command = ENV['CXX']
++  end
+ 
+   # Use mrbgems
+   # conf.gem 'examples/mrbgems/ruby_extension_example'
+@@ -16,6 +28,9 @@
+   # include the GEM box
+   conf.gembox 'default'
+ 
++  conf.gem '../mgems/mruby-env'
++  conf.gem '../mgems/mruby-marshal-c'
++
+   # C compiler settings
+   # conf.cc do |cc|
+   #   cc.command = ENV['CC'] || 'gcc'
+@@ -79,5 +79,5 @@
+   # Turn on `enable_debug` for better debugging
+   # conf.enable_debug
+-  conf.enable_bintest
+-  conf.enable_test
++  # conf.enable_bintest
++  # conf.enable_test
+ end