WL#4738 streamline/simplify @@variable creation process

Bug#16565 mysqld --help --verbose does not order variablesBug#20413 sql_slave_skip_counter is not shown in show variables
Bug#20415 Output of mysqld --help --verbose is incomplete
Bug#25430 variable not found in SELECT @@global.ft_max_word_len;
Bug#32902 plugin variables don't know their names
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#34829 No default value for variable and setting default does not raise error
Bug#34834 ? Is accepted as a valid sql mode
Bug#34878 Few variables have default value according to documentation but error occurs  
Bug#34883 ft_boolean_syntax cant be assigned from user variable to global var.
Bug#37187 `INFORMATION_SCHEMA`.`GLOBAL_VARIABLES`: inconsistent status
Bug#40988 log_output_basic.test succeeded though syntactically false.
Bug#41010 enum-style command-line options are not honoured (maria.maria-recover fails)
Bug#42103 Setting key_buffer_size to a negative value may lead to very large allocations 
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#44797 plugins w/o command-line options have no disabling option in --help
Bug#46314 string system variables don't support expressions
Bug#46470 sys_vars.max_binlog_cache_size_basic_32 is broken
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#47212 Crash in DBUG_PRINT in mysqltest.cc when trying to print octal number
Bug#48758 mysqltest crashes on sys_vars.collation_server_basic in gcov builds
Bug#49417 some complaints about mysqld --help --verbose output
Bug#49540 DEFAULT value of binlog_format isn't the default value
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
Bug#49646 mysql --show-warnings crashes when server dies


CMakeLists.txt:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
client/mysql.cc:
  don't crash with --show-warnings when mysqld dies
config/ac-macros/plugins.m4:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
include/my_getopt.h:
  comments
include/my_pthread.h:
  fix double #define
mysql-test/mysql-test-run.pl:
  run sys_vars suite by default
  properly recognize envirinment variables (e.g. MTR_MAX_SAVE_CORE) set to 0
  escape gdb command line arguments
mysql-test/suite/sys_vars/r/rpl_init_slave_func.result:
  init_slave+utf8 bug
mysql-test/suite/sys_vars/t/rpl_init_slave_func.test:
  init_slave+utf8 bug
mysys/my_getopt.c:
  Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
  Bug#46586 When using the plugin interface the type "set" for options caused a crash.
  Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
mysys/typelib.c:
  support for flagset
sql/ha_ndbcluster.cc:
  backport from telco tree
sql/item_func.cc:
  Bug#49644 init_connect and \0
  Bug#49645 init_slave and multi-byte characters
sql/sql_builtin.cc.in:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
sql/sql_plugin.cc:
  Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
  Bug#32902 plugin variables don't know their names
  Bug#44797 plugins w/o command-line options have no disabling option in --help
sql/sys_vars.cc:
  all server variables are defined here
storage/myisam/ft_parser.c:
  remove unnecessary updates of param->quot
storage/myisam/ha_myisam.cc:
  myisam_* variables belong here
strings/my_vsnprintf.c:
  %o and %llx
unittest/mysys/my_vsnprintf-t.c:
  %o and %llx tests
vio/viosocket.c:
  bugfix: fix @@wait_timeout to work with socket timeouts (vs. alarm thread)

include/my_getopt.h

@@ -32,6 +32,7 @@ C_MODE_START
 #define GET_ENUM      12
 #define GET_SET       13
 #define GET_DOUBLE    14
+#define GET_FLAGSET   15
 
 #define GET_ASK_ADDR	 128
 #define GET_TYPE_MASK	 127
@@ -42,24 +43,40 @@ struct st_typelib;
 
 struct my_option
 {
-  const char *name;                     /* Name of the option */
-  int        id;                        /* unique id or short option */
-  const char *comment;                  /* option comment, for autom. --help */
-  uchar      **value;                   /* The variable value */
-  uchar      **u_max_value;             /* The user def. max variable value */
-  struct st_typelib *typelib;           /* Pointer to possible values */
-  ulong     var_type;
-  enum get_opt_arg_type arg_type;
-  longlong   def_value;                 /* Default value */
-  longlong   min_value;                 /* Min allowed value */
-  longlong   max_value;                 /* Max allowed value */
-  longlong   sub_size;                  /* Subtract this from given value */
-  long       block_size;                /* Value should be a mult. of this */
-  void       *app_type;                 /* To be used by an application */
+  const char *name;                     /**< Name of the option. name=NULL
+                                           marks the end of the my_option[]
+                                           array.
+                                         */
+  int        id;                        /**< For 0<id<255 it's means one
+                                           character for a short option
+                                           (like -A), if >255 no short option
+                                           is created, but a long option still
+                                           can be identified uniquely in the
+                                           my_get_one_option() callback.
+                                           If an opton needs neither special
+                                           treatment in the my_get_one_option()
+                                           nor one-letter short equivalent
+                                           use id=0
+                                         */
+  const char *comment;                  /**< option comment, for autom. --help.
+                                           if it's NULL the option is not
+                                           visible in --help.
+                                         */
+  uchar      **value;                   /**< A pointer to the variable value */
+  uchar      **u_max_value;             /**< The user def. max variable value */
+  struct st_typelib *typelib;           /**< Pointer to possible values */
+  ulong     var_type;                   /**< GET_BOOL, GET_ULL, etc */
+  enum get_opt_arg_type arg_type;       /**< e.g. REQUIRED_ARG or OPT_ARG */
+  longlong   def_value;                 /**< Default value */
+  longlong   min_value;                 /**< Min allowed value (for numbers) */
+  longlong   max_value;                 /**< Max allowed value (for numbers) */
+  longlong   sub_size;                  /**< Unused                          */
+  long       block_size;                /**< Value should be a mult. of this (for numbers) */
+  void       *app_type;                 /**< To be used by an application */
 };
 
-typedef my_bool (* my_get_one_option) (int, const struct my_option *, char * );
-typedef void (* my_error_reporter) (enum loglevel level, const char *format, ... );
+typedef my_bool (*my_get_one_option) (int, const struct my_option *, char * );
+typedef void (*my_error_reporter) (enum loglevel level, const char *format, ... );
 
 extern char *disabled_my_option;
 extern my_bool my_getopt_print_errors;
@@ -78,6 +95,8 @@ ulonglong getopt_ull_limit_value(ulonglong num, const struct my_option *optp,
                                  my_bool *fix);
 longlong getopt_ll_limit_value(longlong, const struct my_option *,
                                my_bool *fix);
+double getopt_double_limit_value(double num, const struct my_option *optp,
+                                 my_bool *fix);
 my_bool getopt_compare_strings(const char *s, const char *t, uint length);
 
 C_MODE_END