Add compiler condition to remove warnings when not using legacy deployment.

Source/Constraint.swift

@@ -315,11 +315,15 @@ internal class ConcreteConstraint: Constraint {
         }
         
         // add constraints
-        if #available(iOS 8.0, OSX 10.7, *) {
+        #if SNAPKIT_DEPLOYMENT_LEGACY && !os(OSX)
+        if #available(iOS 8.0, *) {
             NSLayoutConstraint.activateConstraints(newLayoutConstraints)
         } else {
             installOnView!.addConstraints(newLayoutConstraints)
         }
+        #else
+            NSLayoutConstraint.activateConstraints(newLayoutConstraints)
+        #endif
         
         // set install info
         self.installInfo = ConcreteConstraintInstallInfo(view: installOnView, layoutConstraints: NSHashTable.weakObjectsHashTable())
@@ -342,11 +346,15 @@ internal class ConcreteConstraint: Constraint {
                 
                 if installedLayoutConstraints.count > 0 {
                     // remove the constraints from the UIView's storage
-                    if #available(iOS 8, OSX 10.7, *) {
+                    #if SNAPKIT_DEPLOYMENT_LEGACY && !os(OSX)
+                    if #available(iOS 8.0, *) {
                         NSLayoutConstraint.deactivateConstraints(installedLayoutConstraints)
                     } else if let installedOnView = installInfo.view {
                         installedOnView.removeConstraints(installedLayoutConstraints)
                     }
+                    #else
+                        NSLayoutConstraint.deactivateConstraints(installedLayoutConstraints)
+                    #endif
                     
                     // remove the constraints from the from item view
                     if let fromView = self.fromItem.view {