Don't dump everything in the global namespace

Makefile

@@ -13,6 +13,7 @@ CXX=em++
 OPTFLAGS=-O3
 CXXFLAGS=-std=c++14 $(OPTFLAGS) -g -I$(CPYTHONINC) -Wno-warn-absolute-paths
 LDFLAGS=\
+	-s MODULARIZE=1 \
 	$(CPYTHONROOT)/installs/python-$(PYVERSION)/lib/libpython$(PYMINOR).a \
   -s "BINARYEN_METHOD='native-wasm'" \
   -s TOTAL_MEMORY=268435456 \

src/pyodide.js

@@ -1,4 +1,3 @@
-var pyodide = {}
 
 {
     let baseURL = "{{DEPLOY}}";
@@ -7,14 +6,17 @@ var pyodide = {}
     wasmXHR.open('GET', wasmURL, true);
     wasmXHR.responseType = 'arraybuffer';
     wasmXHR.onload = function() {
+        let Module = {};
+
         if (wasmXHR.status === 200 || wasmXHR.status === 0) {
-            pyodide.wasmBinary = wasmXHR.response;
+            Module.wasmBinary = wasmXHR.response;
         } else {
             alert("Couldn't download the pyodide.asm.wasm binary.  Response was " + wasmXHR.status);
         }
 
-        pyodide.baseURL = baseURL;
+        Module.baseURL = baseURL;
         var script = document.createElement('script');
+        script.onload = function() { window.pyodide = pyodide(Module); };
         script.src = baseURL + "pyodide.asm.js";
         document.body.appendChild(script);
     };