Restore mobi target

Makefile

@@ -2,7 +2,7 @@ CHAPTERS := $(basename $(shell ls [0-9][0-9]_*.md) .md)
 
 SVGS := $(wildcard img/*.svg)
 
-all: html book.pdf book_mobile.pdf book.epub
+all: html book.pdf book_mobile.pdf book.epub book.mobi
 
 html: $(foreach CHAP,$(CHAPTERS),html/$(CHAP).html) html/js/acorn_codemirror.js \
       code/skillsharing.zip code/solutions/20_3_a_public_space_on_the_web.zip html/js/chapter_info.js
@@ -75,3 +75,6 @@ epub/hints.xhtml: $(foreach CHAP,$(CHAPTERS),$(CHAP).md) src/extract_hints.js sr
 
 epubcheck: book.epub
 	epubcheck book.epub 2>&1 | grep -v 'img/.*\.svg'
+
+book.mobi: book.epub img/cover.jpg
+	ebook-convert book.epub book.mobi --output-profile=kindle --cover=img/cover.jpg --remove-first-image

html/Eloquent_JavaScript.mobi

@@ -0,0 +1 @@
+../book.mobi

html/index.html

@@ -110,13 +110,11 @@ <h2>Other pages</h2>
     <li><a href="code">Code sandbox and exercise solutions</a></li>
     <li><a href="errata.html">Errata for the paper book</a></li>
     <li><a href="Eloquent_JavaScript.pdf">This book as a single PDF file</a> (&amp; <a href="Eloquent_JavaScript_small.pdf">small version for mobile</a>)</li>
-    <li><a href="http://eloquentjavascript.net/Eloquent_JavaScript.epub">This book as an EPUB file</a></li>
-<!--
-    <li><a href="http://eloquentjavascript.net/Eloquent_JavaScript.mobi">This book as a MOBI (Kindle) file</a></li>
--->
+    <li><a href="https://eloquentjavascript.net/Eloquent_JavaScript.epub">This book as an EPUB file</a></li>
+    <li><a href="https://eloquentjavascript.net/Eloquent_JavaScript.mobi">This book as a MOBI (Kindle) file</a></li>
     <li><a href="https://gitter.im/Eloquent-JavaScript/Lobby">Community chat for readers</a></li>
-    <li><a href="http://eloquentjavascript.net/1st_edition">The first edition of the book</a></li>
-    <li><a href="http://eloquentjavascript.net/2nd_edition">The second edition of the book</a></li>
+    <li><a href="https://eloquentjavascript.net/1st_edition">The first edition of the book</a></li>
+    <li><a href="https://eloquentjavascript.net/2nd_edition">The second edition of the book</a></li>
   </ul>
 
   <h2>Translations of the second edition</h2>