compile-time deprecation reminders

remove old deprecation helpers that were not used anywhere.

create new deprecation helpers and enforce their usage

this also removes inconsistencies in reporting deprecation:
sometimes it was ER_WARN_DEPRECATED_SYNTAX (1287),
sometimes ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT (1681),
sometimes a warning, sometimes a note.

it should always be
* ER_WARN_DEPRECATED_SYNTAX
* a warning (because it's something actionable, not purely informational)

sql/sql_class.h

@@ -8220,5 +8220,7 @@ public:
 LEX_CSTRING make_string(THD *thd, const char *start_ptr,
                         const char *end_ptr);
 
+#include "deprecation.h"
+
 #endif /* MYSQL_SERVER */
 #endif /* SQL_CLASS_INCLUDED */