[purge.c] get rid of stupid limitation in approx_phi()
[purge.c] get rid of stupid limitation in approx_phi()

mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs,mancoast/cado-nfs