This changeset fixes the problem where mysql, when run as a service,
can't "detect" it's own data directory.


sql/mysqld.cc:
  When running on Windows we check to see if we have a hard path in 
  my_progname.  If not, then we use GetModuleFilename to get the full path
  for the executing module.  This allows the program to determine where
  it's at when running as a service.