* libtiff/tif_dir.c (TIFFAdvanceDirectory): If nextdir is found to
be defective, then set it to zero before returning error in order
to terminate processing of truncated TIFF.  Issue found and fix
suggested by Richard Nolde.

* tools/gif2tiff.c: fix possible OOB write (#2452, CVE-2013-4244)
* tools/tiff2pdf.c: terminate after failure of allocating
* tools/tiffinfo.c: Default various values fetched with