diff -up ./libs/base/include/mrpt/math/eigen_plugins.h.eigen306 ./libs/base/include/mrpt/math/eigen_plugins.h

--- ./libs/base/include/mrpt/math/eigen_plugins.h.eigen306	2013-01-04 18:23:15.000000000 -0500

+++ ./libs/base/include/mrpt/math/eigen_plugins.h	2013-04-13 13:14:34.512745092 -0400

@@ -33,6 +33,9 @@

    | POSSIBILITY OF SUCH DAMAGE.                                               |

    +---------------------------------------------------------------------------+ */

+#ifndef EIGEN_PLUGIN_H

+#define EIGEN_PLUGIN_H

+

 // -------------------------------------------------------------------------

 // Note: This file will be included within the body of Eigen::MatrixBase

 // -------------------------------------------------------------------------

@@ -868,4 +871,4 @@ public:

 			for (size_t dst_col_blk=0;dst_col_blk

 				out.coeffRef(dst_row_blk,dst_col_blk) = this->coeff(indices[dst_row_blk],indices[dst_col_blk]);

 	}

-

+#endif