Fixed broken selector signature.

src/cocoa_window.m

@@ -686,7 +686,7 @@ static GLboolean createWindow(_GLFWwindow* window,
     [window->NS.object setAcceptsMouseMovedEvents:YES];
     [window->NS.object center];
 
-    if ([window->NS.object respondsToSelector:@selector(setRestorable)])
+    if ([window->NS.object respondsToSelector:@selector(setRestorable:)])
         [window->NS.object setRestorable:NO];
 
     return GL_TRUE;