[asdf-devel] Ordering of system :depends-on elements

[Anton Vodonosov]

If given system name "mcclim/freetype" we want
ASDF to search for mcclim.asd, then the extension hook
should be named *sysdef-file-search-functions* instead
of *system-definition-search-functions*.

That would allow the the strategy of fallback to the
main system name to be encapsulated in the main ASDF.
And still have the code organization reflecting what is really going on:
ASDF tries to load system "mcclim/freetype"
and asks the extensions for find the "mcclim.asd" file.

Of course, deploying this solution today is complicated - all clients
must attach to new hook. So probably it is easier to just duplicate
the fallback policy in the clients.

P.S. If it is necessary to support people who keep several
system definitions in a single .asd file, then it makes sense
to apply the same strategy to dash separated system names:
search for "mcclim-freetype" may fallback to search in mcclim.asd