Fix define for ssl_conf_curves()
This is a security feature, it shouldn't be optional.
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index 122c1ee..e074ce2 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -375,7 +375,7 @@
mbedtls_md_type_t mbedtls_ssl_md_alg_from_hash( unsigned char hash );
-#if defined(MBEDTLS_SSL_SET_CURVES)
+#if defined(MBEDTLS_ECP_C)
int mbedtls_ssl_curve_is_acceptable( const mbedtls_ssl_context *ssl, mbedtls_ecp_group_id grp_id );
#endif