Add warning if absolute path is used for executable
Add warning if absolute path is used for executable

dbeyer/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,sosy-lab/benchexec,dbeyer/benchexec,sosy-lab/benchexec,dbeyer/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,sosy-lab/benchexec