In LispWorks 6.1 for Macintosh and earlier versions, create-universal-binary
creates a universal binary from two mono-architecture LispWorks images. It must be called only in a LispWorks for Macintosh image that is itself a universal binary.
In LispWorks 7.0 and later versions, universal binaries are not supported and hence create-universal-binary
simply signals an error.
LispWorks User Guide and Reference Manual - 13 Feb 2015