Update of glibc patch from MySQL 4.0

Changed some status variable names
Fix bug in GRANT ... PASSWORD string

mysql_copyright to replace it

Made detection of GNU tar a bit more flexible.
Only use /usr/local/mysql-glibc if it actually exists

  Play safe and set a MySQL 1 - 12 byte BLOB reference to zero except for the length and pointer areas in it

  Monty said an SQL NULL BLOB field must have NULL as the data pointer value

  Add some diagnostic code to track BLOB bugs if they were not already fixed with the change in row0sel.c
row0sel.c:
  Fix a seg fault which was caused inside MySQL because InnoDB when returning a BLOB value did not initialize the length and the data pointer of a BLOB whose value is the SQL NULL; also fix a very improbable race condition which could occur if a row with an externally stored BLOB was fetched using the adaptive hash index

into balfor.local:/home/zak/bk/mysql

(Thanks to Georg Richter!)

Hack to get MIT-pthreads to compile with glibc 2.2

see dev-private email from sasha, subject:
URGENT: rpl_sporadic_master

  Fix an assertion failure in row0ins.c line 511 in case of a cascading delete caused by circularly referencing rows, when foreign keys are used

Added copyright messages to some files that was missing it.

Fixed stack overflow checking with crash-me with gcc 3.0.4
Using @@unknown_variable doesn't hang client anymore
Added @@VERSION variable

  Prevent use of X86 assembler when WIN64 defined