add libc6-dev to build requirements (sys/xattr.h)
add libc6-dev to build requirements (sys/xattr.h)

Gangbiao/cvmfs,Gangbiao/cvmfs,Moliholy/cvmfs,Moliholy/cvmfs,alhowaidi/cvmfsNDN,cvmfs/cvmfs,trshaffer/cvmfs,Gangbiao/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,cvmfs/cvmfs,DrDaveD/cvmfs,djw8605/cvmfs,djw8605/cvmfs,Moliholy/cvmfs,reneme/cvmfs,djw8605/cvmfs,cvmfs/cvmfs,alhowaidi/cvmfsNDN,reneme/cvmfs,DrDaveD/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,cvmfs/cvmfs,alhowaidi/cvmfsNDN,djw8605/cvmfs,djw8605/cvmfs,Gangbiao/cvmfs,alhowaidi/cvmfsNDN,Moliholy/cvmfs,trshaffer/cvmfs,Moliholy/cvmfs,cvmfs/cvmfs,Gangbiao/cvmfs,trshaffer/cvmfs,DrDaveD/cvmfs,reneme/cvmfs,alhowaidi/cvmfsNDN,trshaffer/cvmfs,DrDaveD/cvmfs,DrDaveD/cvmfs,trshaffer/cvmfs,cvmfs/cvmfs,cvmfs/cvmfs