Revert of Remove RegExp.multiline accessors.

src/js/regexp.js

Index: src/js/regexp.js
diff --git a/src/js/regexp.js b/src/js/regexp.js
index 09c59227b3d76faf864f3816032433a67d33d59e..495ba37fe9a5fdb662b132283cac6d1b1be93960 100644
--- a/src/js/regexp.js
+++ b/src/js/regexp.js
@@ -367,6 +367,25 @@
 %DefineAccessorPropertyUnchecked(GlobalRegExp, '$_', RegExpGetInput,
                                  RegExpSetInput, DONT_ENUM | DONT_DELETE);
 
+// The properties multiline and $* are aliases for each other.  When this
+// value is set in SpiderMonkey, the value it is set to is coerced to a
+// boolean.  We mimic that behavior with a slight difference: in SpiderMonkey
+// the value of the expression 'RegExp.multiline = null' (for instance) is the
+// boolean false (i.e., the value after coercion), while in V8 it is the value
+// null (i.e., the value before coercion).
+
+// Getter and setter for multiline.
+var multiline = false;
+var RegExpGetMultiline = function() { return multiline; };
+var RegExpSetMultiline = function(flag) { multiline = flag ? true : false; };
+
+%DefineAccessorPropertyUnchecked(GlobalRegExp, 'multiline', RegExpGetMultiline,
+                                 RegExpSetMultiline, DONT_DELETE);
+%DefineAccessorPropertyUnchecked(GlobalRegExp, '$*', RegExpGetMultiline,
+                                 RegExpSetMultiline,
+                                 DONT_ENUM | DONT_DELETE);
+
+
 var NoOpSetter = function(ignored) {};