Update docs: native build default, cross-compilation, embedding.

doc/install.html

@@ -50,14 +50,8 @@ For the impatient (on POSIX systems):
 make && sudo make install
 </pre>
 <p>
-LuaJIT currently builds out-of-the box on all popular x86 systems
-(Linux, Windows, OSX etc.). It builds and runs fine as a 32&nbsp;bit
-application under x64-based systems, too.
-</p>
-<p style="color: #00a000;">
-The x64 port of LuaJIT is still preliminary and not enabled by default.
-It only builds on Linux/x64 and Windows/x64 right now. If you want to
-give it a try, please follow the special build instructions below.
+LuaJIT currently builds out-of-the box on all popular x86 or x64 systems
+(Linux, Windows, OSX etc.).
 </p>
 
 <h2>Configuring LuaJIT</h2>
@@ -85,13 +79,8 @@ any settings.
 <p>
 Depending on your distribution, you may need to install a package for
 GCC (GCC 3.4 or later required), the development headers and/or a
-complete SDK.
-</p>
-<p>
-E.g. on a current Debian/Ubuntu, install <tt>libc6-dev</tt>
-with the package manager. Currently LuaJIT builds as a 32&nbsp;bit
-application by default, so you actually need to install <tt>libc6-dev-i386</tt>
-when building on an x64 OS.
+complete SDK. E.g. on a current Debian/Ubuntu, install <tt>libc6-dev</tt>
+with the package manager.
 </p>
 <p>
 Download the current source package (pick the .tar.gz), if you haven't
@@ -111,14 +100,9 @@ which is probably the default on your system, anyway. Simply run:
 <pre class="code">
 make
 </pre>
-<div style="color: #00a000;">
 <p>
-You can force a native x64 build on Linux/x64 with the following command:
+This always builds a native x86 or x64 binary, depending on your OS.
 </p>
-<pre class="code">
-make CC="gcc -m64"
-</pre>
-</div>
 <p>
 By default modules are only searched under the prefix <tt>/usr/local</tt>.
 You can add an extra prefix to the search paths by appending the
@@ -203,14 +187,12 @@ Open a "Windows SDK Command Shell" and select the x86 compiler:
 <pre class="code">
 setenv /release /x86
 </pre>
-<div style="color: #00a000;">
 <p>
 Or select the x64 compiler:
 </p>
 <pre class="code">
 setenv /release /x64
 </pre>
-</div>
 <p>
 Then <tt>cd</tt> to the directory where you've unpacked the sources
 and run these commands:
@@ -254,6 +236,53 @@ absolute path names &mdash; all modules are loaded relative to the
 directory where <tt>luajit.exe</tt> is installed
 (see <tt>src/luaconf.h</tt>).
 </p>
+
+<h2>Cross-compiling LuaJIT</h2>
+<p>
+The build system has limited support for cross-compilation. For details
+check the comments in <tt>src/Makefile</tt>. Here are some popular examples:
+</p>
+<p>
+You can cross-compile to a 32 bit binary on a multilib x64 OS by
+installing the multilib development pacakges (e.g. <tt>libc6-dev-i386</tt>
+on Debian/Ubuntu) and running:
+</p>
+<pre class="code">
+make CC="gcc -m32"
+</pre>
+<p>
+You can cross-compile for a Windows target on Debian/Ubuntu by
+installing the <tt>mingw32</tt> package and running:
+</p>
+<pre class="code">
+make CC="gcc -m32" CROSS=i586-mingw32msvc- TARGET_SYS=Windows
+</pre>
+
+<h2>Embedding LuaJIT</h2>
+<p>
+LuaJIT is API-compatible with Lua 5.1. If you've already embedded Lua
+into your application, you probably don't need to do anything to switch
+to LuaJIT, except link with a different library. Additional hints:
+</p>
+<ul>
+<li>Make sure you use <tt>luaL_newstate</tt>. Avoid using
+<tt>lua_newstate</tt>, since this uses the (slower) default memory
+allocator from your system (no support for this on x64).</tt></li>
+<li>Make sure you use <tt>luaL_openlibs</tt> and not the old Lua 5.0 style
+of calling <tt>luaopen_base</tt> etc. directly.</li>
+<li>To change which standard libraries to load, copy <tt>src/lib_init.c</tt>
+to your project and modify it accordingly. Make sure the <tt>jit</tt>
+library is loaded or the JIT compiler will not be activated.</li>
+<li>Here's a
+<a href="http://lua-users.org/wiki/SimpleLuaApiExample"><span class="ext">&raquo;</span>&nbsp;simple example</a>.</li>
+</ul>
+<p>
+64 bit applications on OSX must be linked with these options
+(only the main executable):
+</p>
+<pre class="code">
+-pagezero_size 10000 -image_base 100000000
+</pre>
 <br class="flush">
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