Hi John!

> Something like this:
> 
> ```
> (define-public gobject-introspection+cairo
>    (hidden-package
>     (package
>       (inherit gobject-introspection)
>       (arguments
>        (substitute-keyword-arguments (package-arguments 
> gobject-introspection)
>          ((#:configure-flags flags ''())
>           `(cons* "-Dcairo=true" ,flags))))
>       (inputs
>        `(("cairo" ,cairo)
>          ,@(package-inputs gobject-introspection))))))
> ```

Or, something like this:

```
(define-public gobject-introspection+cairo
   (hidden-package
    (package
      (inherit gobject-introspection)
      (arguments
       (substitute-keyword-arguments (package-arguments 
gobject-introspection)
         ((#:configure-flags flags ''())
          `(append
            (list
             "-Dcairo=true"
             (string-append "-Dcairo_libname="
                            (assoc-ref %build-inputs "cairo")
                            "/lib/libcairo-gobject.so"))
            ,flags))))
      (inputs
       `(("cairo" ,cairo)
         ,@(package-inputs gobject-introspection))))))
```

Regards,
RG.