Pass around typmod as int16.

src/backend/access/common/printtup.c

src/backend/access/common/tupdesc.c

src/backend/commands/copy.c

src/backend/executor/nodeGroup.c

src/backend/executor/nodeUnique.c

src/backend/executor/spi.c

src/backend/libpq/be-dumpdata.c

src/backend/nodes/makefuncs.c

src/backend/nodes/outfuncs.c

src/backend/nodes/readfuncs.c

src/backend/parser/parse_expr.c

src/backend/parser/parse_func.c

src/backend/parser/parse_node.c

src/backend/parser/parse_target.c

src/backend/parser/parse_type.c

src/backend/utils/adt/varchar.c

src/backend/utils/cache/lsyscache.c

src/include/access/tupdesc.h

src/include/catalog/pg_attribute.h

src/include/catalog/pg_type.h