Hi All, I think that you are right Salvatore, the bug is likely to come from libspectre. I currently experience the same problem from a stable Jessie and with the Atril reader. I compiled libspectre 0.2.7 from source and was able to restore functionality by interfering with the commands sent from the library to Ghostscript. It seems (according to http://git.savannah.gnu.org/cgit/guix.git/commit/?id=1de17a648fa631f0074d315bfff0716220ce4880) that they modified the behavior of ".locksafe", so I just filtered it away within spectre_gs_send_string and the reader is working again. However, I have no idea if this hack is a correct/stable approach to the problem.
Sincerely, Ronan