Added dummy c++ file to make library compile even if no enable_ldl

nonlinear/Makefile.am

@@ -17,8 +17,9 @@ check_PROGRAMS += tests/testLieConfig
 
 # Nonlinear nonlinear 
 headers += NonlinearFactorGraph.h NonlinearFactorGraph-inl.h
-headers += NonlinearOptimizer.h NonlinearOptimizer-inl.h 
+headers += NonlinearOptimizer-inl.h 
 headers += NonlinearFactor.h
+sources += NonlinearOptimizer.cpp
 
 # Nonlinear constraints 
 headers += NonlinearConstraint.h NonlinearConstraint-inl.h

nonlinear/NonlinearOptimizer.cpp

@@ -0,0 +1,15 @@
+/**
+ * NonlinearOptimizer.cpp
+ * @brief: Dummy c++ file to have *something* in lin-nonlinear if USE_LDL not defined.
+ * @Author: Frank Dellaert
+ * Created on: Jul 17, 2010
+ */
+
+#pragma once
+
+#include "NonlinearOptimizer.h"
+
+namespace gtsam {
+
+
+}