feat: openkal 0.4.0 — two rules a portable program found, and the packages that follow them - #223

The specification states two rules it previously did not, and both were found by
writing one program against it and running it rather than by reading it.

An implementation passes the argument vector unaltered, so the started program
observes the name the caller chose. Both implementations prepended the path;
they agreed only because they shared an author. Enquiry about a name that does
not exist succeeds and reports absence, while opening the same name reports that
it was not found — enquiry and access are different operations.

Neither rule changes a declaration, so the exported surface is unchanged and an
implementation conforming to 0.3 exports exactly what 0.4 requires. What changed
is behaviour the earlier version left open, which is why each package takes a
minor revision.

Earlier versions are replaced rather than retained, on the same reasoning as
before: an implementation that conformed to the earlier specification may fail
to conform to this one, and two incompatible specifications under one name would
be worse than the absence of the earlier.

openkal-libc reaches 0.2.0 for a different reason. Every test in it failed to
link, because the package declares against the interface and links against no
implementation — correct for the package, wrong for its own tests, which run.
The diagnostic was the one clause 4.2 describes, and this is the first occasion
on which that claim was tested by something other than a demonstration built to
test it.