how to install fuzzystrmatch.sql pg_trgm.sql on postgresql on mac os x

I have installed postgresql according to this, but I also need fuzzy string match functions, but I have no idea how to install these.

From serverfault Alex. S.

• Usually with a sql file full of functions, it is something like this:

  cat fuzzystrmatch.sql | psql {database name}
  

  Alex. S. : the problem is, where can I get that file?, it isn't in my system.

  Milen A. Radev : Ask the guys from "PostgreSQL for Mac".
  From jedberg

• For the Mac, the .sql files are in a folder such as /Library/PostgreSQL/8.3/share/postgresql/contrib

  Clinton Blackmore : For me, it was in /Library/PostgresPlus/8.3/share/contrib .
  From Frank J