Support FreeBSD

Author: cjgu

rubygem/bin/ejson2env

@@ -4,6 +4,7 @@ platform = `uname -sm`
 dir = case platform
       when /^Darwin/    ; "darwin-amd64"
       when /^Linux.*64/ ; "linux-amd64"
+      when /^FreeBSD.*64/ ; "freebsd-amd64"
       else
         abort "Ejson is not supported on your platform."
       end