title: Create utility like Linux "df", based on source code of this utility
body: <p>In university a have task - find source code of utility <code>df</code>, and using it code - create my own simple utility like <code>df</code>. 
  But then I simply tried to compile source code of it (file df.c) from (for ex) <a href="http://lingrok.org/xref/coreutils/src/df.c#ncolumns" rel="nofollow">this site</a> - gcc compilation has errors with library and a lot of other errors..
  On first step - when I do:</p>
  
  <pre><code>gcc -o df.out df.c
  </code></pre>
  
  <p>I have this error: </p>
  
  <pre><code>df.c:21:20: fatal error: config.h: no such file.
  </code></pre>
  
  <p>But in /usr/lib folders in my pc there is this file. What's wrong? Or what is another way to create my own <code>df</code> utility?</p>