gcc: silent compilation warnings

compute/pzlatms.c

control/descriptor.c

control/descriptor_rec.c

runtime/starpu/codelets/codelet_zlantr.c

runtime/starpu/control/runtime_descriptor.c

runtime/starpu/interface/cham_tile_interface.c

testing/testing_zcesca.c

testing/testing_zgram.c

testing/testing_zhemm.c

testing/testing_zprint.c

testing/testing_zsymm.c

testing/testing_ztrmm.c

testing/testing_zunmlq.c

testing/testing_zunmlq_hqr.c

testing/testing_zunmqr.c

testing/testing_zunmqr_hqr.c