2016-10-14 Patrick Galbraith, Michiel Beijen, DBI/DBD community (4.037_01)
* Newest versions of libmysqlclient and the MariaDB C connector no longer
  export the __WIN__ macro. If this macro is not present we would not
  compile in the poll.h-based async-support. Changed to use the _WIN32
  macro instead. Thanks to Sergei Golubchik for suggesting the fix.