modifying ./configure for EXTERNAL_BINARY

[Graham Percival]

Would it be possible to add an option to ./configure so that it only 
looks for programs required to build the docs with GUB?

If I'm only building the docs, I don't need things like libguile, do I? 
 I obviously need the guile runtime stuff, but those are included in 
GUB.  I also need software like texinfo and latex... but it would still 
simplify doc compiling greatly.

This would be helpful for more people than just me; a couple of doc 
helpers have wanted to build the docs themselves (so that they could 
test patches before sending them to me), but have been unable to do so. 
 I don't mind doing the extra testing, but it would be nice if they 
could do it themselves.

Cheers,
- Graham