Let them come and they will build it!
My former teacher Paul Romer has written a thoughtful post on how to help the millions of refugees who would relocate to Western countries, if only they were allowed to do so. I highly recommend following the link about to read it in full. His basic idea is to let the refugees build themselves cities. Cities are economic powerhouses; refugees want dignity and work, not only handouts for basic survival. Put these ideas together and prosper, Western countries.