> The build is failing because it can't find the library for  
> FXScintilla, which is an optional component that FXRuby can use  
> when it's present:
>
> 	http://www.fxruby.org/doc/scintilla.html
>
> So, for some reason, the FXRuby installation script thought that  
> FXScintilla was installed on your computer and it configured the  
> build that way. The way that FXRuby "decides" whether or not you  
> have FXScintilla is installed is by looking for the FXScintilla  
> include files; it looks for any of the following:
>
> 	/usr/include/fxscintilla/fxscintilla.h
> 	/usr/local/include/fxscintilla/fxscintilla.h
> 	/sw/include/fxscintilla/fxscintilla.h (this is where Fink installs  
> it)
> 	/opt/local/include/fxscintilla/fxscintilla.h (this is where  
> MacPorts installs it)
>
> Since you mentioned that you've experimented with Fink before, I  
> have a suspicion that a copy of fxscintilla.h is still hanging  
> around in the /sw/include/fxscintilla directory (but you should  
> check all four locations to be sure). Remove that, and then start  
> over:
>
> 	sudo rm -rf /sw/include/fxscintilla
> 	sudo gem install fxruby

Spot on. I've removed the dir and in the process of trying it again.
My wife's just popped her head around the door 'Where are you? I  
though you were coming to bed?' Better go :)
I'll let you know how things go tomorrow.

Cheers,
Dave