WL#1054: Pluggable authentication support

Merged the implementation to a new base tree.

sql/sql_class.h

@@ -862,9 +862,13 @@ public:
     priv_user - The user privilege we are using. May be "" for anonymous user.
     ip - client IP
   */
-  char   *host, *user, *priv_user, *ip;
+  char   *host, *user, *ip;
+  char   priv_user[USERNAME_LENGTH];
+  char   proxy_user[USERNAME_LENGTH + MAX_HOSTNAME + 5];
   /* The host privilege we are using */
   char   priv_host[MAX_HOSTNAME];
+  /* The external user (if available) */
+  char   *external_user;
   /* points to host if host is available, otherwise points to ip */
   const char *host_or_ip;
   ulong master_access;                 /* Global privileges from mysql.user */
@@ -2100,7 +2104,8 @@ public:
   char	     scramble[SCRAMBLE_LENGTH+1];
 
   bool       slave_thread, one_shot_set;
-  bool	     no_errors, password;
+  bool	     no_errors;
+  uchar      password;
   /**
     Set to TRUE if execution of the current compound statement
     can not continue. In particular, disables activation of
@@ -2910,6 +2915,11 @@ my_eof(THD *thd)
 #define reenable_binlog(A)   (A)->variables.option_bits= tmp_disable_binlog__save_options;}
 
 
+LEX_STRING *
+make_lex_string_root(MEM_ROOT *mem_root,
+                     LEX_STRING *lex_str, const char* str, uint length,
+                     bool allocate_lex_string);
+
 /*
   Used to hold information about file and file structure in exchange
   via non-DB file (...INTO OUTFILE..., ...LOAD DATA...)