add missing -fopenmp flag for ncc_compute_shift compilation
add missing -fopenmp flag for ncc_compute_shift compilation

jmichel-otb/s2p,mnhrdt/s2p,dyoussef/s2p,MISS3D/s2p,jmichel-otb/s2p,MISS3D/s2p,mnhrdt/s2p,MISS3D/s2p,dyoussef/s2p,dyoussef/s2p,jmichel-otb/s2p,MISS3D/s2p,dyoussef/s2p,carlodef/s2p,carlodef/s2p,jmichel-otb/s2p