The first one is libjpeg's fault for a while now and for many programs. I think the debian people edit libjpeg.h and remove the declaration in their packages, it creates this warning for everyone using autoconf with libjpeg. To get rid of it, complain to libjpeg developers, or edit libjpeg.h and remove bogus #define. You might *have* to, I think gcc 4.3 makes it an error now.