I disabled the test in is_funky and found that it was still taking ages to
compute 'whatsnew -s'.  After a fair bit of debugging trying to figure out where
the culprit is, I found that it may be a problem with reading the pending or
what we do with the pending after we read it.

The attached patch passes all the tests on my system, but may not be the correct
way to solve the problem.  Also, I have tried to send this patch twice once to
darcs-devel and once to darcs-users, but both times it was silently ignored. 
I'm not sure why.