use a browser sub for the streams vs event emitter switch

_internal_stream-browser.js

@@ -0,0 +1 @@
+module.exports = require('events').EventEmitter;

_internal_stream.js

@@ -0,0 +1 @@
+module.exports = require('stream');

build/files.js

@@ -111,11 +111,7 @@ const headRegexp = /(^module.exports = \w+;?)/m
     , requireStreamReplacement = [
       /const Stream = require\('stream'\);/
     ,  '\n\n/*<replacement>*/\n'
-      + 'var Stream;\nif (process.browser){\n'
-      + '    Stream = require(\'events\').EventEmitter;\n'
-      + '} else {\n'
-      + '  Stream = require(\'st\' + \'ream\');\n'
-      + '}'
+      + 'var Stream = require(\'../_internal_stream\')'
       + '\n/*</replacement>*/\n'
     ]
 

lib/_stream_readable.js

@@ -25,12 +25,7 @@ var EElistenerCount = function (emitter, type) {
 /*</replacement>*/
 
 /*<replacement>*/
-var Stream;
-if (process.browser) {
-  Stream = require('events').EventEmitter;
-} else {
-  Stream = require('st' + 'ream');
-}
+var Stream = require('../_internal_stream');
 /*</replacement>*/
 
 var Buffer = require('buffer').Buffer;

lib/_stream_writable.js

@@ -32,12 +32,7 @@ var internalUtil = {
 /*</replacement>*/
 
 /*<replacement>*/
-var Stream;
-if (process.browser) {
-  Stream = require('events').EventEmitter;
-} else {
-  Stream = require('st' + 'ream');
-}
+var Stream = require('../_internal_stream');
 /*</replacement>*/
 
 var Buffer = require('buffer').Buffer;

package.json

@@ -42,7 +42,8 @@
     "util": false,
     "./readable.js": "./readable-browser.js",
     "./writable.js": "./writable-browser.js",
-    "./duplex.js": "./duplex-browser.js"
+    "./duplex.js": "./duplex-browser.js",
+    "./_internal_stream.js": "./_internal_stream-browser.js"
   },
   "react-native": {
     "stream": false