0580a7b4c6
A potential conflict arises should should some program attempt to access systemd data using our library built without that support (--disable-systemd). And while we could argue that all callers should check against NULL string pointers, it's not expected of libprocps users. So we'll guarantee 'em valid string consisting of "?". Reference(s): http://www.freelists.org/post/procps/systemd-binary-vs-library Signed-off-by: Jim Warner <james.warner@comcast.net>