Voilà qui est encore mieux !!!
OCTAVE_FILES = $$files($${PWD}/scripts/*.m)
copy_files.name = Copy scripts
copy_files.input = OCTAVE_FILES
copy_files.output = $${OUT_PWD}/data/${QMAKE_FILE_BASE}${QMAKE_FILE_EXT}
copy_files.commands = ${COPY_FILE} ${QMAKE_FILE_IN} ${QMAKE_FILE_OUT}
copy_files.CONFIG += no_link target_predeps
QMAKE_EXTRA_COMPILERS += copy_files