// Experimentally determined
private static final int auto = 0;
private static final int internalOnly = 1;
private static final int preferExternal = 2;

AssetManager am = createPackageContext(packageName, 0).getAssets();
XmlResourceParser xml = am.openXmlResourceParser("AndroidManifest.xml");
int eventType = xml.getEventType();
xmlloop:
while (eventType != XmlPullParser.END_DOCUMENT) {
    switch (eventType) {
        case XmlPullParser.START_TAG:
            if (! xml.getName().matches("manifest")) {
                break xmlloop;
            } else {
                attrloop:
                for (int j = 0; j < xml.getAttributeCount(); j++) {
                    if (xml.getAttributeName(j).matches("installLocation")) {
                        switch (Integer.parseInt(xml.getAttributeValue(j))) {
                            case auto:
                                // Do stuff
                                break;
                            case internalOnly:
                                // Do stuff
                                break;
                            case preferExternal:
                                // Do stuff
                                break;
                            default:
                                // Shouldn't happen
                                // Do stuff
                                break;
                        }
                        break attrloop;
                    }
                }
            }
            break;
        }
        eventType = xml.nextToken();
    }