[T] added error message

Tests/MathLib/TestODESolver.cpp

@@ -68,7 +68,13 @@ std::unique_ptr<MathLib::ODESolver<NumEquations>> make_ode_solver(
 {
 	// Make sure testrunner does not crash if we haven't built with support for
 	// any external ODE solver lib.
-	if (!any_ode_solver_libs_available()) return nullptr;
+	if (!any_ode_solver_libs_available())
+	{
+		ERR(
+		    "I cannot create any ODE solver. This test therefore might be "
+		    "skipped.");
+		return nullptr;
+	}
 
 	BaseLib::ConfigTree config(conf, "", BaseLib::ConfigTree::onerror,
 	                           BaseLib::ConfigTree::onwarning);