[Libguestfs] Usage of 'no' as external helper

libguestfs and supermin use 'no' instead of either the basename of the desired application, or 'false', as helper string. This happens when configure does not find things like rpm or supermin during build. Wouldnt it be more logical to use the basename instead of 'no' so that at runtime one has the chance to install the required packages and in addition get an obvious error message in verbose mode what external helper is actually missing? In my package I force a few things like 'export ZYPPER=zypper' to avoid the unneeded BuildRequires: zypper. But doing that for every binary that maybe called is cumbersome. I think its best to rely on PATH to let libguestfs and supermin packages find their external helpers at runtime. And one who has a need to actually hardcode absolute paths to external helpers into his libguestfs/supermin binaries can do that by doing the 'export HELPER=/path/to/helper' during his own configure run. Thoughts? Olaf