port doesn't exit with proper return value

[Joshua Root]

Port's normal mode of operation is to run as many of the requested 
commands as possible and not exit when a command fails. It does this by 
suppressing the error status from the commands. This is certainly 
incorrect when there's only one command run and it fails, but it's less 
clear what should happen when some of the requested commands succeed.

You can make the first failed command cause port to exit, with the 
appropriate return code, by using the -x option on the command line.

Related tickets:

http://trac.macports.org/ticket/13918
http://trac.macports.org/ticket/14928

- Josh