arbitration of multiple master_sites

[markd at macports.org]

>> -Sourceforge, gnu, etc., special mirrors go after sorted url list
>
>No. They get mixed in with the other master_sites and sorted.

So if we had this master_sites keyword in port foo:

master_sites \
     sourceforge \                 (ping resp t9)
     ftp://example1.org \    (ping resp t4)
     http://example2.org \  (ping resp t7)
     freebsd                           (ping resp t1)

The fetch order of the master_sites would be:

1) freebsd
2) ftp://example1.org
3) http://example2.org
4) sourceforge
5) implicit MP fallback mirrors

And the individual url's listed in mirrors_sites.tcl for mirrors are tried
in order.  Is that understanding correct?

Mark