Bug#31177: Server variables can't be set to their current values

additional fixes for 64-bit
---
Merge mysql.com:/misc/mysql/31177/50-31177
into  mysql.com:/misc/mysql/31177/51-31177
---
Bug#31177: Server variables can't be set to their current values

additional 5.1 fixes (for plugins)

mysql-test/t/variables.test

@@ -141,7 +141,7 @@ set GLOBAL myisam_max_sort_file_size=2000000;
 show global variables like 'myisam_max_sort_file_size';
 select * from information_schema.global_variables where variable_name like 'myisam_max_sort_file_size';
 set GLOBAL myisam_max_sort_file_size=default;
---replace_result 2147483647 FILE_SIZE 2146435072 FILE_SIZE
+--replace_result 2147483647 FILE_SIZE 9223372036854775807 FILE_SIZE
 show variables like 'myisam_max_sort_file_size';
 --replace_result 2147483647 FILE_SIZE 9223372036854775807 FILE_SIZE
 select * from information_schema.session_variables where variable_name like 'myisam_max_sort_file_size';

mysys/my_getopt.c

@@ -867,7 +867,7 @@ ulonglong getopt_ull_limit_value(ulonglong num, const struct my_option *optp,
                                  bool *fix)
 {
   bool adjusted= FALSE;
-  ulonglong old= num, mod;
+  ulonglong old= num;
   char buf1[255], buf2[255];
 
   if ((ulonglong) num > (ulonglong) optp->max_value &&
@@ -892,6 +892,8 @@ ulonglong getopt_ull_limit_value(ulonglong num, const struct my_option *optp,
       num= ((ulonglong) ULONG_MAX);
       adjusted= TRUE;
     }
+#else
+    num= min(num, LONG_MAX);
 #endif
     break;
   default:

sql/sql_plugin.cc

@@ -1880,7 +1880,13 @@ static int check_func_int(THD *thd, struct st_mysql_sys_var *var,
   struct my_option options;
   value->val_int(value, &tmp);
   plugin_opt_set_limits(&options, var);
-  *(int *)save= (int) getopt_ull_limit_value(tmp, &options, &fixed);
+
+  if (var->flags & PLUGIN_VAR_UNSIGNED)
+    *(uint *)save= (uint) getopt_ull_limit_value((ulonglong) tmp, &options,
+                                                   &fixed);
+  else
+    *(int *)save= (int) getopt_ll_limit_value(tmp, &options, &fixed);
+
   if (fixed)
   {
     char buf[22];
@@ -1902,7 +1908,13 @@ static int check_func_long(THD *thd, struct st_mysql_sys_var *var,
   struct my_option options;
   value->val_int(value, &tmp);
   plugin_opt_set_limits(&options, var);
-  *(long *)save= (long) getopt_ull_limit_value(tmp, &options, &fixed);
+
+  if (var->flags & PLUGIN_VAR_UNSIGNED)
+    *(ulong *)save= (ulong) getopt_ull_limit_value((ulonglong) tmp, &options,
+                                                   &fixed);
+  else
+    *(long *)save= (long) getopt_ll_limit_value(tmp, &options, &fixed);
+
   if (fixed)
   {
     char buf[22];
@@ -1925,6 +1937,13 @@ static int check_func_longlong(THD *thd, struct st_mysql_sys_var *var,
   value->val_int(value, &tmp);
   plugin_opt_set_limits(&options, var);
   *(ulonglong *)save= getopt_ull_limit_value(tmp, &options, &fixed);
+
+  if (var->flags & PLUGIN_VAR_UNSIGNED)
+    *(ulonglong *)save= getopt_ull_limit_value((ulonglong) tmp, &options,
+                                               &fixed);
+  else
+    *(longlong *)save= getopt_ll_limit_value(tmp, &options, &fixed);
+
   if (fixed)
   {
     char buf[22];