Re: [PATCH] remove delta-against-self bit

Nicolas Pitre [off-list ref] writes:

Said bit would in fact be more useful to allow for encoding the copying 
of chunks larger than 64KB providing more savings with large files.  
This will correspond to packs version 3.

While the current code still produces packs version 2, it is made future 
proof so pack versions 2 and 3 are accepted.  Any pack version 2 are 
compatible with version 3 since the redefined bit was never used before.  
When enough time has passed, code to use that bit to produce version 3 
packs could be added.

I agree with the general direction and this futureproofing is a
good thing to have before 1.2.0, I think.

The bit is however _already_ looked at by the count_delta(),
to assess the extent of damage, IIRC.  Should we be
futureproofing that bit as well?