Add PS4 port.

Thanks to Eddie Edwards.

doc/install.html

@@ -120,7 +120,7 @@ operating systems, CPUs and compilers:
 <tr class="even">
 <td class="compatcpu">x64 (64 bit)</td>
 <td class="compatos">GCC 4.x</td>
-<td class="compatos compatno">&nbsp;</td>
+<td class="compatos">ORBIS (<a href="#ps4">PS4</a>)</td>
 <td class="compatos">GCC 4.x</td>
 <td class="compatos">MSVC + SDK v7.0<br>WinSDK v7.0</td>
 </tr>
@@ -460,7 +460,7 @@ make HOST_CC="gcc -m32 -arch i386" CROSS=$ISDKP TARGET_FLAGS="$ISDKF" \
 </pre>
 <p>
 You can cross-compile for <b id="ps3">PS3</b> using the PS3&nbsp;SDK from
-a Linux host or a Windows host (requires 32 bit MinGW (GCC) on the host,
+a Linux host or a Windows host (requires 32&nbsp;bit MinGW (GCC) on the host,
 too). Due to restrictions on consoles, the JIT compiler is disabled and
 only the fast interpreter is built:
 </p>
@@ -468,6 +468,22 @@ only the fast interpreter is built:
 make HOST_CC="gcc -m32" CROSS=ppu-lv2-
 </pre>
 <p>
+You can cross-compile for <b id="ps4">PS4</b> from a Windows host using
+the PS4&nbsp;SDK (ORBIS) plus 64&nbsp;bit MSVC. Due to restrictions on
+consoles, the JIT compiler is disabled and only the fast interpreter
+is built.
+</p>
+<p>
+Open a "Visual Studio .NET Command Prompt" (64&nbsp;bit host compiler),
+<tt>cd</tt> to the directory where you've unpacked the sources and run
+the following commands. This builds a static library <tt>libluajit.a</tt>,
+which can be linked against your game, just like the Lua library.
+</p>
+<pre class="code">
+cd src
+ps4build
+</pre>
+<p>
 You can cross-compile for <b id="xbox360">Xbox 360</b> using the
 Xbox&nbsp;360 SDK (MSVC + XEDK). Due to restrictions on consoles, the
 JIT compiler is disabled and only the fast interpreter is built.