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

os_thread_count transition to Atomic_counter.

storage/innobase/include/os0thread.h

@@ -73,7 +73,7 @@ typedef unsigned int    mysql_pfs_key_t;
 #endif /* HAVE_PSI_INTERFACE */
 
 /** Number of threads active. */
-extern	ulint	os_thread_count;
+extern	Atomic_counter<ulint>	os_thread_count;
 
 /***************************************************************//**
 Compares two thread ids for equality.

storage/innobase/os/os0thread.cc

@@ -28,7 +28,7 @@ Created 9/8/1995 Heikki Tuuri
 #include "srv0srv.h"
 
 /** Number of threads active. */
-ulint	os_thread_count;
+Atomic_counter<ulint>	os_thread_count;
 
 /***************************************************************//**
 Compares two thread ids for equality.
@@ -118,7 +118,7 @@ os_thread_create_func(
 
 	CloseHandle(handle);
 
-	my_atomic_addlint(&os_thread_count, 1);
+	os_thread_count++;
 
 	return((os_thread_t)new_thread_id);
 #else /* _WIN32 else */
@@ -127,7 +127,7 @@ os_thread_create_func(
 
 	pthread_attr_init(&attr);
 
-	my_atomic_addlint(&os_thread_count, 1);
+	os_thread_count++;
 
 	int	ret = pthread_create(&new_thread_id, &attr, func, arg);
 
@@ -182,7 +182,7 @@ os_thread_exit(bool detach)
 	pfs_delete_thread();
 #endif
 
-	my_atomic_addlint(&os_thread_count, ulint(-1));
+	os_thread_count--;
 
 #ifdef _WIN32
 	ExitThread(0);