FLI type descriptor
fixnum type and a Cshort type. fli
:short &optional integer-type
interger-type ::= :int
If specified, must be:int, which associates a Lispfixnum with a Cint.
:short type associates a Lispfixnum with a Cshort. :short,(:short :int),(:signed :short), and(:signed :short :int) are equivalent. :int :signed