title: Variably modified at file scope error
body: <p>I've a perfectly working program that has a following struct</p>
  
  <pre><code>typedef struct SERVER{
      int id;
      char ip_addr[MAX_IP + 1];
      int port;
  }SERVER;
  </code></pre>
  
  <p>MAX_IP is defined in a header file.</p>
  
  <pre><code>#define MAX_IP strlen("255.255.255.255")
  </code></pre>
  
  <p>This code runs fine on my local machine. The moment I upload it to a server I get the following compilation error.</p>
  
  <pre><code>objs.h:4:10: error: variably modified ‘ip_addr’ at file scope
       char ip_addr[MAX_IP + 1];
  </code></pre>
  
  <p>What could possibly be wrong.</p>