Rick suggested it would be nice to have something to allow inspection of enabled roles, cf the
ENABLED_ROLES view of the information schema, SQL 2003, vol 11, section 5.29.
I enclose patch suggestion for doing this via a new VTI table and syntactic sugar in ij:
SYSCS_DIAG.ENABLED_ROLES and and ij command "show enabled_roles".
Not for commit at this point, we may want to handle to general question of information schemata
in another way. What say thee?