[PATCH wayland-web] Adding notes regarding Arch Linux dependencies for DocBook.

[Jon A. Cruz]

Adding simple notes on DocBook dependencies needed when building on Arch Linux.
Without these being present the documentation build will attempt network access
and fail outright or warn and then not produce correct results when no Internet
access is present.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=86515

Signed-off-by: Jon A. Cruz <jonc at osg.samsung.com>
---
 building.html | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/building.html b/building.html
index 401069b..fbedfae 100644
--- a/building.html
+++ b/building.html
@@ -42,6 +42,8 @@ Linux Mint 17</a>, which is derived from Ubuntu 14.04.</li>
 <li>For building Weston for <a href="http://www.raspberrypi.org/">Raspberry
 Pi</a>, see <a href="raspberrypi.html">Raspberry Pi build guide</a>.</li>
 
+<li>For building Wayland on Arch note that <a href="https://wiki.archlinux.org/index.php/Docbook#Setting_up_Docbook_in_Arch">DocBook dependencies</a> will be needed when building documentation.</li>
+
 </ul>
 
 <h2>Hardware / Drivers</h2>
@@ -119,6 +121,8 @@ $ cd ..
 <li>You can avoid the <a href="http://www.stack.nl/~dimitri/doxygen/">Doxygen</a> dependency
 with <code>--disable-documentation</code>.</li>
 
+<li>Under Arch Linux,  <a href="https://wiki.archlinux.org/index.php/Docbook#Setting_up_Docbook_in_Arch">DocBook dependencies</a> will be needed when building documentation. These include <code>docbook-xml</code> and <code>docbook-xsl</code>.</li>
+
 </ul>
 
 <h2>Mesa</h2>
-- 
1.9.1