> It seems like *all* occurrences of

> 	include "some.foo.file"

> in a config file need to be changed to

> 	include "arch/foo/conf/some.foo.file"

That is correct.  I should have said so, but for some reason I had
assumed that the std.foo files were the only examples.

> From earlier discussion, I'd thought that an "machine foo bar" line
> in "foo.std" was sufficient to put arch/foo/conf (and arch/bar/conf)
> on config's include search-path.

It was a proposal, but the responses I got argued against it.  There's
no "include search-path"; all includes are relative to the source
directory and nothing else.