fix a race condition in TC_LOG_BINLOG::unlog


include/Makefile.am:
  remove the rest of isam/merge references
include/config-win.h:
  unused and abused macro removed
include/my_pthread.h:
  unused and abused macro removed
include/my_sys.h:
  MY_IGNORE_BADFD flag
include/mysql_embed.h:
  remove the rest of isam/merge references
mysql-test/r/replace.result:
  remove the rest of isam/merge references
mysql-test/t/replace.test:
  remove the rest of isam/merge references
mysql-test/t/xa.test:
  comment
mysys/my_sync.c:
  MY_IGNORE_BADFD flag
sql/handler.cc:
  remove the rest of isam/merge references
sql/log.cc:
  fix a race condition in TC_LOG_BINLOG::unlog
  preparation for binlog group commit
sql/mysql_priv.h:
  remove duplicates
sql/mysqld.cc:
  remove the rest of isam/merge references
sql/opt_range.cc:
  remove the rest of isam/merge references
sql/set_var.cc:
  hide unused variables. simplify sync_binlog code
sql/sql_base.cc:
  remove the rest of isam/merge references
sql/sql_class.h:
  cleanup