[J3] 18-265 and the PROTECTED attribute

[Van Snyder]

In 18-265, Bill proposed a PROTECTED attribute for components.

14-165r1 proposed a PROTECTED attribute for types.  14-165r1 proposed
that the PROTECTED attribute could be specified for a type only in the
scoping unit of a module.  It would be useful to be able to specify it
for a type accessed by host association.

A colleague recently requested a PROTECTED annotation for USE to
prohibit changing variables accessed by use association.  He also
proposed a PROTECTED attribute for variables accessed by host
association.  It would endure for the scope in which it is declared.
Like ASYNCHRONOUS and VOLATILE, it doesn't create a new variable if it's
specified for a variable accessed by host association.

PROTECTED, in all the proposed forms and uses, ought to be considered as
a single sub-work-item related to container support.