Update docs about exception handling.

doc/api.html

@@ -318,11 +318,11 @@ exceptions. If you're embedding LuaJIT into an application, only
 enable it <b>after</b> running <tt>luaL_openlibs</tt>.
 </p>
 <p>
-LuaJIT already intercepts exception handling for systems using
-DWARF2 stack unwinding (e.g. Linux, OSX). This is a zero-cost mechanism
-and always enabled. You don't need to use any wrapper functions,
-except when you want to get a more specific error message than
-<tt>"C++&nbsp;exception"</tt>.
+LuaJIT already intercepts exception handling for all x64 systems and
+for x86 systems using DWARF2 stack unwinding (e.g. Linux, OSX). This
+is a zero-cost mechanism and always enabled. You don't need to use any
+wrapper functions, except when you want to get a more specific error
+message than <tt>"C++&nbsp;exception"</tt>.
 </p>
 <br class="flush">
 </div>