autogen.sh: add uuid, handle non-existent config.h
autogen.sh: add uuid, handle non-existent config.h

pestophagous/unofficial_scratchpad_git-cvsimport_libexif,pestophagous/unofficial_scratchpad_git-cvsimport_libexif,pestophagous/unofficial_scratchpad_git-cvsimport_libexif