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

additional fixes for 64-bit

mysql-test/t/variables.test

@@ -126,7 +126,7 @@ set GLOBAL query_cache_size=100000;
 set GLOBAL myisam_max_sort_file_size=2000000;
 show global variables like 'myisam_max_sort_file_size';
 set GLOBAL myisam_max_sort_file_size=default;
---replace_result 2147482624 FILE_SIZE 2146435072 FILE_SIZE
+--replace_result 9223372036853727232 FILE_SIZE 2146435072 FILE_SIZE
 show variables like 'myisam_max_sort_file_size';
 
 set global net_retry_count=10, session net_retry_count=10;

mysys/my_getopt.c

@@ -799,7 +799,7 @@ 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 &&
@@ -824,6 +824,8 @@ 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: