Hmm.. you're right. I have no clue why rpm doesn't call find-debuginfo.sh... ;-(

If I directly call the "%debug_package" macro from my spec file it works as
expected. So the %install macro is probably bad.

The readahead doesn't use any subdirectory for sources (there is not tarball,
all code is directly in the sourcedir).

Your not calling %setup so the buildsubdir isn't set.  Really the sources should
be in a released tar ball not just in CVS work around by 

%prep 
%setup -T -c

I suggest you also copy %{SOURCE0} to pwd after setup and compile it there so
debuginfo can find the source.

Fixed. I've created tarball -- it's probably the best solution which avoids all
current and future problems.