Handle pthread_rwlock_t as opaque mutex in base analysis

Avoids unsound rwlock struct content invariants in witnesses.

src/cdomain/value/cdomains/valueDomain.ml

@@ -120,7 +120,7 @@ struct
     | _ -> false
 
   let is_mutex_type (t: typ): bool = match t with
-    | TNamed (info, attr) -> info.tname = "pthread_mutex_t" || info.tname = "spinlock_t" || info.tname = "pthread_spinlock_t" || info.tname = "pthread_cond_t"
+    | TNamed (info, attr) -> info.tname = "pthread_mutex_t" || info.tname = "spinlock_t" || info.tname = "pthread_spinlock_t" || info.tname = "pthread_cond_t" || info.tname = "pthread_rwlock_t"
     | TInt (IInt, attr) -> hasAttribute "mutex" attr
     | _ -> false