Make the IterativeLinearSolvers module compatible with MPL2-only mode

by defaulting to COLAMDOrdering and NaturalOrdering for ILUT and ILLT respectively.

test/CMakeLists.txt

@@ -223,6 +223,7 @@ ei_add_test(prec_inverse_4x4)
 ei_add_test(vectorwiseop)
 ei_add_test(special_numbers)
 ei_add_test(rvalue_types)
+ei_add_test(mpl2only)
 
 ei_add_test(simplicial_cholesky)
 ei_add_test(conjugate_gradient)

test/mpl2only.cpp

@@ -0,0 +1,20 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2015 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#define EIGEN_MPL2_ONLY
+#include <Eigen/Dense>
+#include <Eigen/SparseCore>
+#include <Eigen/SparseLU>
+#include <Eigen/SparseQR>
+#include <Eigen/IterativeLinearSolvers>
+
+int main()
+{
+  return 0;
+}