Added a thread-safe and robust wrapper for APR pools.

See http://redmine.imprudenceviewer.org/issues/590
and https://jira.secondlife.com/browse/SNOW-596

indra/newview/llappviewerlinux.cpp

@@ -139,6 +139,7 @@ int main( int argc, char **argv )
 	}
 	delete viewer_app_ptr;
 	viewer_app_ptr = NULL;
+
 	return 0;
 }