in build-i18n.js, add selective module export and allow underscore im…

…porting.

build-i18n.js

@@ -1,3 +1,7 @@
+// If args are specified on the command line, assume they are
+// module names, and only export their localizations.
+var MODULE_FILTER = process.argv.slice(2);
+
 var NLS_PATHS = [
   'fc/nls',
   'slowparse-errors/nls'
@@ -8,13 +12,21 @@ var requirejs = require('requirejs');
 var requireConfig = require('./js/require-config');
 var bundles = {};
 
+// For some reason r.js doesn't like our default underscore shim.
+requireConfig.shim['underscore'].exports = '_';
+
 requirejs.config(requireConfig);
 
 NLS_PATHS.forEach(function(path) {
   fs.readdirSync(__dirname + '/js/' + path).forEach(function(filename) {
     var match = filename.match(/^(.*)\.js$/);
     if (match) {
       var moduleName = path + '/' + match[1];
+
+      if (MODULE_FILTER.length &&
+          MODULE_FILTER.indexOf(moduleName) == -1)
+        return;
+
       var bundle = requirejs(moduleName);
 
       bundles[moduleName] = bundle;