Added test to show bug in current union implementation

After merge fixes
Portability fixes


client/mysqltest.c:
  Fixed that unget() is done properly (needed for QNX where one can't do many ungetc() in a row)
include/errmsg.h:
  After merge fixes
mysql-test/mysql-test-run.sh:
  merge fix
mysql-test/r/system_mysql_db.result:
  Updated results for 4.1
mysql-test/r/union.result:
  Added new test
mysql-test/t/derived.test:
  Portability fix (for Mac OS X)
mysql-test/t/system_mysql_db_refs.test:
  Remove warnings
mysql-test/t/union.test:
  Added test to show bug in current union implementation (to be fixed in 4.1)
scripts/mysql_create_system_tables.sh:
  Fix wrong column define
scripts/mysql_fix_privilege_tables.sh:
  Fix for mysql-test-run
scripts/mysql_fix_privilege_tables.sql:
  Merge with 4.0 to get comments.
  Updated so that it works with privilege tables for MySQL 3.23.
sql/repl_failsafe.cc:
  After merge fix

mysql-test/t/system_mysql_db_refs.test

@@ -10,27 +10,39 @@ set @name="This is a very long string, that mustn't find room in a system field
 
 create table test_db select * from mysql.db;
 delete from test_db;
+--disable_warnings
 insert into test_db (Host,Db,User) values (@name,@name,@name);
+--enable_warnings
 
 create table test_host select * from mysql.host;
 delete from test_host;
+--disable_warnings
 insert into test_host (Host,Db) values (@name,@name);
+--enable_warnings
 
 create table test_user select * from mysql.user;
 delete from test_user;
+--disable_warnings
 insert into test_user (Host,User) values (@name,@name);
+--enable_warnings
 
 create table test_func select * from mysql.func;
 delete from test_func;
+--disable_warnings
 insert into test_func (name) values (@name);
+--enable_warnings
 
 create table test_tables_priv select * from mysql.tables_priv;
 delete from test_tables_priv;
+--disable_warnings
 insert into test_tables_priv (Host,Db,User,Table_name) values (@name,@name,@name,@name);
+--enable_warnings
 
 create table test_columns_priv select * from mysql.columns_priv;
 delete from test_columns_priv;
+--disable_warnings
 insert into test_columns_priv (Host,Db,User,Table_name,Column_name) values (@name,@name,@name,@name,@name);
+--enable_warnings
 
 # 'Host' field must be the same for all the tables: