[gobject-introspection] (8 commits) ...Correct logic for legacy ffi free_closure

[Emmanuele Bassi <ebassi src gnome org>]

Summary of changes:

  2b3153e... Open g-i for 1.71 development (*)
  62c3c95... girffi.c: fix return value for g_callable_info_prepare_clos (*)
  2a4dede... girffi.h: add g_callable_info_get_closure_native_address()  (*)
  55a18f5... Create new API for libffi closures (*)
  d81cad5... Avoid leaking memory from FFI closure if no segfault risk (*)
  3da41e1... Fix styling issues from suggestions (*)
  f8ea3c9... Remove runtime warnings, add doxygen deprecation notices (*)
  d4d5fb2... Correct logic for legacy ffi free_closure (*)

(*) This commit already existed in another branch; no separate mail sent