Cleanup strict build.

Former-commit-id: c34b2e7e2810e8bc35bde3e0f962d925b3f5ba1b

build.js

@@ -1153,13 +1153,12 @@
    * @returns {String} Returns the modified source.
    */
   function setUseStrictOption(source, value) {
-    // inject "use strict"
-    if (value) {
-      source = source.replace(/^[\s\S]*?function[^{]+{/, "$&\n  'use strict';");
-    }
+    // inject or remove the "use strict" directive
+    source = source.replace(/(^[\s\S]*?function[^{]+{)(?:\s*'use strict';)?/, '$1' + (value ? "\n  'use strict';" : ''));
+
     // replace `strict` branch in `iteratorTemplate` with hard-coded option
     source = source.replace(getIteratorTemplate(source), function(match) {
-      return match.replace(/(?: *\/\/.*\n)*(\s*)["'] *<%.+?strict.+/, value ? '$1"\'use strict\';\\n" +' : '');
+      return match.replace(/(template\()(?:\s*"'use strict.+)?/, '$1' + (value ? '\n    "\'use strict\';\\n" +' : ''));
     });
 
     return source;

lodash.js

@@ -354,9 +354,6 @@
    * @returns {String} Returns the interpolated text.
    */
   var iteratorTemplate = template(
-    // conditional strict mode
-    "<% if (obj.useStrict) { %>'use strict';\n<% } %>" +
-
     // the `iteratee` may be reassigned by the `top` snippet
     'var index, iteratee = <%= firstArg %>, ' +
     // assign the `result` variable an initial value