girepository: Add length ‘out’ arguments to several getter methods
This makes them consistent with the other getter methods in
GIRepository
which return lists/arrays. It’s useful to return the
length, as that means the caller doesn’t have to work it out by
iterating over the entire array.
Signed-off-by: Philip Withnall pwithnall@gnome.org
Helps: #3155 (closed)