Don't lie about the supported architectures in the OSX installer

Without this patch the i386/x86_64 installer for OSX 10.6
lies in the ReadMe file and the "Important Information" screen
of the installer (that is, the installer claims it supports
the i386 and ppc architectures insetead of the ones it really
supports)

Mac/BuildScript/build-installer.py

@@ -866,7 +866,7 @@ def patchFile(inPath, outPath):
     data = data.replace('$FULL_VERSION', getFullVersion())
     data = data.replace('$VERSION', getVersion())
     data = data.replace('$MACOSX_DEPLOYMENT_TARGET', ''.join((DEPTARGET, ' or later')))
-    data = data.replace('$ARCHITECTURES', "i386, ppc")
+    data = data.replace('$ARCHITECTURES', ", ".join(universal_opts_map[UNIVERSALARCHS]))
     data = data.replace('$INSTALL_SIZE', installSize())
 
     # This one is not handy as a template variable