diff -up gpaw-1.2.0-8963a4467f21f43a491933d0ce2ac2949eed77cb/c/xc/libxc.c.libxc4 gpaw-1.2.0-8963a4467f21f43a491933d0ce2ac2949eed77cb/c/xc/libxc.c
--- gpaw-1.2.0-8963a4467f21f43a491933d0ce2ac2949eed77cb/c/xc/libxc.c.libxc4	2017-02-07 12:46:55.000000000 +0100
+++ gpaw-1.2.0-8963a4467f21f43a491933d0ce2ac2949eed77cb/c/xc/libxc.c	2017-10-23 16:44:56.175146939 +0200
@@ -798,10 +798,12 @@ lxcXCFunctional_tb09(lxcXCFunctionalObje
     PyArrayObject* tau_g;
     PyArrayObject* v_g;
     PyArrayObject* vx_g;  // for vsigma, vtau, vlapl
+    double params[1];
     if (!PyArg_ParseTuple(args, "dOOOOOO",
                           &c, &n_g, &sigma_g, &lapl_g, &tau_g, &v_g, &vx_g))
         return NULL;
-    xc_mgga_x_tb09_set_params(self->functional[0], c);
+    params[0] = c;
+    xc_func_set_ext_params(self->functional[0], params);
     xc_mgga_vxc(self->functional[0], PyArray_DIM(n_g, 0),
                 PyArray_DATA(n_g),
                 PyArray_DATA(sigma_g),