windows: use USERPROFILE to get the user's home dir

Fixes nodejs#3461
Close nodejs#3462
Close nodejs#4093

Author: piscisaureus

lib/module.js

@@ -497,16 +497,24 @@ Module.runMain = function() {
   Module._load(process.argv[1], null, true);
 };
 
-Module._initPaths = function() {
+Module._initPaths = function () {
+  var isWindows = process.platform === 'win32';
+
+  if (isWindows) {
+    var homeDir = process.env.USERPROFILE;
+  } else {
+    var homeDir = process.env.HOME;
+  }
+
   var paths = [path.resolve(process.execPath, '..', '..', 'lib', 'node')];
 
-  if (process.env['HOME']) {
-    paths.unshift(path.resolve(process.env['HOME'], '.node_libraries'));
-    paths.unshift(path.resolve(process.env['HOME'], '.node_modules'));
+  if (homeDir) {
+    paths.unshift(path.resolve(homeDir, '.node_libraries'));
+    paths.unshift(path.resolve(homeDir, '.node_modules'));
   }
 
   if (process.env['NODE_PATH']) {
-    var splitter = process.platform === 'win32' ? ';' : ':';
+    var splitter = isWindows ? ';' : ':';
     paths = process.env['NODE_PATH'].split(splitter).concat(paths);
   }