Repair for non-ECC OpenSSL.
Ifdef out the ECC parts when building with an OpenSSL that doesn't have
it.
diff --git a/ssh-keyscan.c b/ssh-keyscan.c
index 2b13030..c5fb3b5 100644
--- a/ssh-keyscan.c
+++ b/ssh-keyscan.c
@@ -282,7 +282,9 @@
c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
+# ifdef OPENSSL_HAS_ECC
c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
+# endif
#endif
c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);