thread: remove acl_is_locked_callback as legacy emulator library is deprecated

Author: sophimao

include/acl_thread.h

@@ -82,9 +82,6 @@ void acl_signal_device_update();
 
 static inline int acl_is_locked() { return (acl_global_lock_count > 0); }
 
-// Used by dynamically loaded libs to check lock status.
-int acl_is_locked_callback(void);
-
 static inline void acl_assert_locked() { assert(acl_is_locked()); }
 
 static inline void acl_assert_locked_or_sig() {

src/acl_thread.cpp

@@ -36,8 +36,6 @@ void acl_mutex_wrapper_t::unlock() {
   }
 }
 
-int acl_is_locked_callback(void) { return (acl_global_lock_count > 0); }
-
 int acl_mutex_wrapper_t::suspend_lock() {
   int old_lock_count = acl_global_lock_count;
   acl_global_lock_count = 0;