bug#9990: valgrind warning in add_row_entry

[Eli Zaretskii]

> From: Dan Nicolaescu <dann@gnu.org>
> Cc: 9990@debbugs.gnu.org
> Date: Tue, 15 Nov 2011 11:58:50 -0500
> 
> > I added a function that verifies the hash value of glyph rows before
> > it is used in row_equal_p, and also in adjust_glyph_matrix, where the
> > offending reallocation takes place.  I cannot trigger the xasserts
> > that use this function when I use "C-h H".  Can you?
> 
> No, I cannot.
> 
> > If the hash values are always correct where they are used, I guess
> > that excludes the possibility that we use an uninitialized value,
> > right?
> 
> I even added an  xassert (verify_row_hash (row)) in add_row_entry, and
> it does not trigger.  Strange...

I have a feeling I didn't interpret the valgrind diagnostics
correctly.  But I don't see any alternative interpretation that would
make sense.