Suggestion - don't require sane and artsc

[Bill Medland]

(Having just been caught by this again !!)

It would be nice if in the distributions we dynamically detected libartsc and 
libsane rather than requiring them.  When someone is installing on a small 
computer they will tend to exclude irrelevant packages like scanner and sound 
software when they don't have a scanner or speakers.

(This paricularly relates to the RedHat 8.0 rpms)