title: "'errno' undeclared" when compile Linux kernel
body: <p>I'm trying to compile and I keep getting the following error:
  <a href="https://i.stack.imgur.com/JXqMZ.jpg" rel="nofollow noreferrer">enter image description here</a></p>
  
  <p>I've included the <code>asm-i386/errno.h</code> once and it didn't work. Also I've tried including <code>linux/errno.h</code> and it didn't work ether.</p>
  
  <p>What file should I include?</p>