Selective transfer of a bugfix patch into 5.5.6-rc.

The first part is the functional change,
the second is needed as a compile fix on Windows
(header file order).

| committer: Marc Alff <marc.alff@oracle.com>
| branch nick: mysql-5.5-bugfixing-56521
| timestamp: Thu 2010-09-09 14:28:47 -0600
| message:
|   Bug#56521 Assertion failed: (m_state == 2), function allocated_to_free, pfs_lock.h (138)
|
|   Before this fix, it was possible to build the server:
|   - with the performance schema
|   - with a dummy implementation of my_atomic (MY_ATOMIC_MODE_DUMMY).
|
|   In this case, the resulting binary will just crash,
|   as this configuration is not supported.
|
|   This fix enforces that the build will fail with a compilation error in this
|   configuration, instead of resulting in a broken binary.

| committer: Tor Didriksen <tor.didriksen@oracle.com>
| branch nick: 5.5-bugfixing-56521
| timestamp: Fri 2010-09-10 11:10:38 +0200
| message:
|   Header files should be self-contained

storage/perfschema/ha_perfschema.cc

@@ -20,6 +20,7 @@
 
 #include "my_global.h"
 #include "my_pthread.h"
+#include "my_atomic.h"
 #include "sql_plugin.h"
 #include "mysql/plugin.h"
 #include "ha_perfschema.h"
@@ -28,6 +29,17 @@
 #include "pfs_instr_class.h"
 #include "pfs_instr.h"
 
+#ifdef MY_ATOMIC_MODE_DUMMY
+/*
+  The performance schema can can not function with MY_ATOMIC_MODE_DUMMY,
+  a fully functional implementation of MY_ATOMIC should be used instead.
+  If the build fails with this error message:
+  - either use a different ./configure --with-atomic-ops option
+  - or do not build with the performance schema.
+*/
+#error "The performance schema needs a functional MY_ATOMIC implementation."
+#endif
+
 handlerton *pfs_hton= NULL;
 
 static handler* pfs_create_handler(handlerton *hton,