mruby.patch

diff --git a/build_config/emscripten.rb b/build_config/emscripten.rb
new file mode 100644
index 000000000..e016f7887
--- /dev/null
+++ b/build_config/emscripten.rb
@@ -0,0 +1,9 @@
+
+MRuby::CrossBuild.new('emscripten') do |conf|
+  toolchain :clang
+  conf.gembox 'wasm'
+  conf.cc.command = 'emcc'
+  conf.cc.flags = %W(-Os)
+  conf.linker.command = 'emcc'
+  conf.archiver.command = 'emar'
+end
diff --git a/mrbgems/wasm.gembox b/mrbgems/wasm.gembox
new file mode 100644
index 000000000..f4eb831e1
--- /dev/null
+++ b/mrbgems/wasm.gembox
@@ -0,0 +1,10 @@
+MRuby::GemBox.new do |conf|
+  conf.gembox "stdlib"
+  conf.gembox "stdlib-io"
+  conf.gembox "stdlib-ext"
+  conf.gembox "metaprog"
+  conf.gembox "math"
+
+  # Add third party json support
+  conf.gem :github => "mattn/mruby-json", :checksum_hash => "054699892b0d681110e7348440cddb70a3fd671e"
+end