title: Use of undeclared identifier FLT_MAX when used in macro
body: <p>I use the following code to dynamically resize labels:</p>
  
  <pre><code>CGRect frame = self.myLabel2.frame;
  frame.origin.y = self.myLabel1.frame.origin.y + self.myLabel1.frame.size.height + 10;
  frame.size = LABEL_SIZE(self.myLabel2);
  self.myLabel2.frame = frame;
  </code></pre>
  
  <p>Where <code>LABEL_SIZE</code> is a macro defined as :</p>
  
  <pre><code>#define LABEL_SIZE(label) CGSizeMake(280, [label sizeThatFits:CGSizeMake(280, FLT_MAX)].height);
  </code></pre>
  
  <p>The code works absolutely fine when run on simulator (32-bit). The problem arises when running  on simulator (64-bit). XCode shows it <em>not</em> as a warning, but as an <strong>error</strong>, due to which, it will not even compile.</p>
  
  <p>I do not understand, am I missing something?</p>