Allow change of system hooks for assuan_sock_...
* src/assuan-socket.c (assuan_sock_set_system_hooks): New. * src/assuan.h.in (assuan_sock_set_system_hooks): New prototype. * src/libassuan.def: Add new function. * src/libassuan.vers: Add new function.
- Co-authored-by: wk@gnupg.org
- Signed-off-by: Werner Koch <wk@gnupg.org>