Hint Resolve ctr_inv_positive.

(* Specifications: *)
Lemma body_incr: semax_body Vprog Gprog f_incr incr_spec.
Lemma body_read : semax_body Vprog Gprog f_read read_spec.
Lemma body_thread_func : semax_body Vprog Gprog f_thread_func thread_func_spec.
Lemma lock_struct : forall p, data_at_ Ews (Tstruct _lock_t noattr) p |-- data_at_ Ews tlock p.
Lemma body_main:  semax_body Vprog Gprog f_main main_spec.
Definition extlink := ext_link_prog prog.