ds:system-subsystems ?

Hi!

I've been working on an extension to Allegro's system definition 
framework but I've sort of hit a dead-end with this. One of the 
features I'm trying to include is the "automatic on-demand load" of 
systems. In order to do this I need to know the subsystems of a given 
system.

There is an unexported system-subsystem function that does what I want 
in the composer package, but no such function in the defsystem package. 
Of course that function is not available under Windows so using it 
isn't the best solution...

What would the "correct" way of doing this be? Map-system doesn't seem 
to be of much help if the system isn't already loaded (in which case 
the subsystems' modules will be available and the containing-system 
function would give me a way of enumerating all systems involved, not 
really useful though). I've also tried looking at list-all-systems, 
which would solve the particular problem of making sure all systems 
were loaded, but that seems to be too much of a hack and would also 
limit me in some other features I'm hoping to implement.

Now that I've shared my frustrations with you all... Any ideas? I found 
it reasonably surprising that no such function already exists.

Thanks for your time,

Tiago Maduro-Dias.