Set default value for last input argument of lyapunov_symm routine (debug flag).

matlab/lyapunov_symm.m

@@ -43,10 +43,15 @@ function [x,u] = lyapunov_symm(a,b,third_argument,lyapunov_complex_threshold,met
 %
 % You should have received a copy of the GNU General Public License
 % along with Dynare.  If not, see <http://www.gnu.org/licenses/>.
+
 if nargin<5 || isempty(method)
     method = 0;
 end
 
+if nargin<7
+    debug = 0;
+end
+
 if method == 3
     persistent X method1;
     if ~isempty(method1)