- Patch #19895 by Moshe: currently modules can inadvertently load all other modules during the bootstrap. this is easy to do by calling a node_load() or module_invoke_all(). this degrades performance for anonymous users when caching is enabled.  With this patch, the module writer will see an php error like "Call to undefined function: drupal_set_html_head()" if this is attempted. basically, unavailable functions are actually reported as unavailable.