certain dig options which were deprecated and became nonoperational
several releases ago still had documentation in the dig man page and
warnings printed when they were used: these included +mapped,
+sigchase, +topdown, +unexpected, +trusted-key, and the -i and -n
options. these are now all fatal errors.
another option was described as deprecated in the man page, but
the code to print a warning was never added. it has been added now.
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