debsigs-installer is designed to be called in an automated fashion from an installer. It is given one or
more files on the command line. For each file, it will apply the origin signature and make sure that the
resulting package verifies (it will fail to verify if it is missing one of the other required
signatures). It will try its best to do either an all or nothing approach; that is, if there is a
problem with any .deb, all of them will be unmodified and error code is returned. It can assure this for
all except system call failures (can't copy files, etc.) If success is returned, all files should be
assumed to have succeeded. If failure is returned, all files should be assumed to have failed.