CC Mode: Prevent ids in temporary "declarators" getting into c-found-types

CC Mode: Prevent ids in temporary "declarators" getting into c-found-types

This should fix bug #60765.  In the scenario type an identifier in front of
foo (bar, baz), as when started a new statement.  This temporarily makes the
function call a declarator, and bar and baz types.  Don't enter bar and baz
into c-found-types.

* lisp/progmodes/cc-engine.el (c-forward-decl-or-cast-1) (CASE 6): When a
'maybe type triggers this case, set `unsafe-maybe' to non-nil.