MDEV-17441 - InnoDB transition to C++11 atomics

dict_table_t::n_foreign_key_checks_running transition to
Atomic_counter.

storage/innobase/include/dict0mem.h

@@ -1746,17 +1746,17 @@ struct dict_table_t {
 	void inc_fk_checks()
 	{
 #ifdef UNIV_DEBUG
-		lint fk_checks= (lint)
+		int32_t fk_checks=
 #endif
-		my_atomic_addlint(&n_foreign_key_checks_running, 1);
+		n_foreign_key_checks_running++;
 		ut_ad(fk_checks >= 0);
 	}
 	void dec_fk_checks()
 	{
 #ifdef UNIV_DEBUG
-		lint fk_checks= (lint)
+		int32_t fk_checks=
 #endif
-		my_atomic_addlint(&n_foreign_key_checks_running, ulint(-1));
+		n_foreign_key_checks_running--;
 		ut_ad(fk_checks > 0);
 	}
 
@@ -1935,7 +1935,7 @@ struct dict_table_t {
 	/** Count of how many foreign key check operations are currently being
 	performed on the table. We cannot drop the table while there are
 	foreign key checks running on it. */
-	ulint					n_foreign_key_checks_running;
+	Atomic_counter<int32_t>			n_foreign_key_checks_running;
 
 	/** Transactions whose view low limit is greater than this number are
 	not allowed to store to the MySQL query cache or retrieve from it.