Provide a way to use regular expressions in MongoDB where the word character (\w) and word boundary (\b) escapes work for code points greater than or equal to 256.

Original description

$regex word boundary fails by treating Danish ø character as a non-character

db.collection.find({ "name" : { "$regex" : ".*\\bden\\b.*" , "$options" : "i"} })

returns a document:

{  "name": "Death Is A Caress(Døden Er Et Kjærtegn).sub" }