Change 'Parse error' to three more informative messages.

src/v8natives.js

Index: src/v8natives.js
diff --git a/src/v8natives.js b/src/v8natives.js
index 83b561859a87b93a2dbefb2a0762475559efc93e..425863e5010fd63f3f9240b051e5007cca2450e7 100644
--- a/src/v8natives.js
+++ b/src/v8natives.js
@@ -1766,7 +1766,7 @@ function NewFunction(arg1) {  // length == 1
     // If the formal parameters string include ) - an illegal
     // character - it may make the combined function expression
     // compile. We avoid this problem by checking for this early on.
-    if (p.indexOf(')') != -1) throw MakeSyntaxError('unable_to_parse',[]);
+    if (p.indexOf(')') != -1) throw MakeSyntaxError('paren_in_arg_string',[]);
     // If the formal parameters include an unbalanced block comment, the
     // function must be rejected. Since JavaScript does not allow nested
     // comments we can include a trailing block comment to catch this.