Creating self contained bundles with MacPorts

[Drew McCormack]

I want to use macports to build self contained bundles, containing a  
tool and any dependencies of that tool. For example, I want to  
distribute an FFTW package that installs into /Users/Shared/FFTW.  
Under that directory would be the usual bin, lib etc:

/Users/Shared/FFTW/bin
/Users/Shared/FFTW/lib ...

Any libraries that FFTW uses would also be included in that bundle.

My question is: how could I do this with macports? I thought it would  
be a simple matter of changing the install prefix in macports.conf:

prefix                  /Users/Shared/FFTW

But when I do this, I get error messages indicating I haven't setup  
the prefix dir properly:

Library directory '/Users/Shared/OpenMacPorts/share/macports/Tcl'  
must exist
     while executing
"mportinit ui_options global_options global_variations"
Error: /opt/local/bin/port: Failed to initialize ports system,  
Library directory '/Users/Shared/OpenMacPorts/share/macports/Tcl'  
must exist

Is there a straightforward way to do what I want? Basically I want to  
have control over the install directory, such that I can change it at  
will.

Drew McCormack
MacResearch.org