Fixed compile time bug

dlib/svm/svm_multiclass_linear_trainer.h

@@ -263,7 +263,7 @@ namespace dlib
         )
         {
             learn_nonnegative_weights = value;
-            if (learns_nonnegative_weights)
+            if (learn_nonnegative_weights)
                 prior = trained_function_type(); 
         }