How to enable trace mode automatically (to hide other ports while building)?

[Mojca Miklavec]

Hi,

I would like to hide a couple of ports while building one specific
port. I know that I can do this with "port -t build foo", but I would
like to do this automatically within the Portfile, otherwise the port
would have to conflict with a whole bunch of other ports without any
good reason (other than the build system picking headers from the
wrong package).

Thank you,
    Mojca