Properly add GetArchName() lua binding.

Docs/Changelog_sm5.txt

@@ -8,6 +8,12 @@ ________________________________________________________________________________
 StepMania 5.0 $next | 2011xxxx
 --------------------------------------------------------------------------------
 
+2011/11/02
+----------
+* [ArchHooks] Add the GetArchName lua binding. To the themers that use
+  GetOSName, that function may be deprecated in the future. For now,
+  both options exist. [vyhd, Wolfman2000]
+
 2011/11/01
 ----------
 * [ArrowEffects] Fix Expand, and possibly other mods, from breaking if

Docs/Luadoc/Lua.xml

@@ -537,6 +537,7 @@
 		</Class>
 		<Class name='ArchHooks'>
 			<Function name='AppHasFocus'/>
+			<Function name='GetArchName'/>
 		</Class>
 		<Class base='BitmapText' name='BPMDisplay'>
 			<Function name='GetText'/>

Docs/Luadoc/LuaDocumentation.xml

@@ -1368,6 +1368,9 @@
 	<Function name='AppHasFocus' return='bool' arguments=''>
 		Returns <code>true</code> if the application presently has focus.
 	</Function>
+	<Function name='GetArchName' return='{string}' arguments=''>
+		Returns the name of the architecture in use.
+	</Function>
 </Class>
 <Class name='Banner'>
 	<Function name='GetScrolling' return='bool' arguments=''>