This patch is optional, and related to the problem that got fixed
by your latest patch series, mentioned in my previous email:
http://www.sourceware.org/ml/gdb-patches/2011-11/msg00799.html

I still noticed a call to skip_prologue_sal without a check of
self->funfirstline.

Perhaps there is no situation where this might make a difference,
but I thought it might be good to add the check anyways, just
to be on the safe side.

-- 
Joel