Add pure attributes to *_get_type() functions
Add an annotater which adds ‘pure’ attributes to *_get_type() functions for GObjects. Double-check first whether the pure attribute is correct for such functions though. (I’m pretty sure it is.)
This could potentially improve optimisations if the plugin were ever used during the normal compilation process (rather than just static analysis).
(Imported from bugs-everywhere; see #2 (closed).)