fixups of test case and comment formatting

This is a second patch needing another review.  The first patch didn't solve
the entire problem.  open and fopen on Windows will still open
files like "com1.sym" when they shouldn't.  This patch
checks that the file exists before trying to open it.

The problem was that on Windows the access method indicates that access to file 
such as "com1" and "lpt1" is allowed (since they are device names) and
this causes mysql to attempt to open them as databases or tables.

The fix was to write our own my_access method that uses other Win32 functions
to determine if the given argument is indeed a file and has to requested
mode.

into mysql.com:/usr/home/ram/work/mysql-4.1

sql_udf.cc:
  changed dl_name to udf->dl in mysql_create_function

into mysql.com:/usr/home/ram/work/mysql-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

into book.sanja.is.com.ua:/Users/bell/mysql/bk/work-4.1

into serg.mylan:/usr/home/serg/Abk/mysql-4.0

when reporting an error, use an appropriate buffer for udf->name

into mysql.com:/home/mydev/mysql-4.1-4100

After review version.
Added a condition for MERGE tables. These do not have unique
indexes. But every key could be a unique key on the underlying
MyISAM table. So get the maximum key length for MERGE tables
instead of the maximum unique key length. This is used for
buffer allocation in write_record().

into mysql.com:/home/jimw/my/mysql-4.1-clean

into mysql.com:/space/pekka/ndb/version/my41

into book.sanja.is.com.ua:/Users/bell/mysql/bk/work-4.1

  Added test cases for bug #7914.
sql_select.cc:
  Fixed bug #7914: rollup over expresssions such as sum(a)+1.

  Added missing ';'.

into serg.mylan:/usr/home/serg/Abk/mysql-4.1

  updated error message for ndb

into mysql.com:/data0/mysqldev/my/mysql-4.1-build

into book.sanja.is.com.ua:/Users/bell/mysql/bk/work-4.1

into mysql.com:/home/psergey/mysql-4.1-bug10095

into mysql.com:/home/psergey/mysql-4.1-bug10221

into mysql.com:/Users/kent/mysql/bk/mysql-4.1

  To solve bug#8455, call mysql_affected_rows() earlier, before query to find warnings

into mysql.com:/home/psergey/mysql-4.0-bug10095