Fix for bug #9571: Primary key creation causes server crash.

sql/unireg.cc:
  Fix for bug #9571: Primary key creation causes server crash.
  We should pass null_pos to the make_field() anyway,
  as we use it for bit fields.

mysql-test/r/type_bit.result

@@ -377,3 +377,6 @@ hex(concat(a))	hex(concat(b))
 07	0FFE
 01	01FF
 drop table t1;
+create table t1(a int, b bit not null);
+alter table t1 add primary key (a);
+drop table t1;

mysql-test/t/type_bit.test

@@ -112,3 +112,11 @@ insert into t1 values (7,(1<<12)-2), (0x01,0x01ff);
 select hex(a),hex(b) from t1;
 select hex(concat(a)),hex(concat(b)) from t1;
 drop table t1;
+
+#
+# Bug #9571: problem with primary key creation
+#
+
+create table t1(a int, b bit not null);
+alter table t1 add primary key (a);
+drop table t1;

sql/unireg.cc

@@ -679,15 +679,14 @@ static bool make_empty_rec(THD *thd, File file,enum db_type table_type,
     null_count++;
   }
   bfill(buff,(null_length=(null_fields+7)/8),255);
-  null_pos=buff;
+  null_pos= buff + null_count / 8;
 
   List_iterator<create_field> it(create_fields);
   thd->count_cuted_fields= CHECK_FIELD_WARN;    // To find wrong default values
   while ((field=it++))
   {
     Field *regfield=make_field((char*) buff+field->offset,field->length,
-			       field->flags & NOT_NULL_FLAG ? 0:
-			       null_pos+null_count/8,
+                               null_pos,
 			       null_count & 7,
 			       field->pack_flag,
 			       field->sql_type,