cmake/maintainer.cmake:
  don't do -Werror just yet
config.h.cmake:
  according to MSDN PSAPI_VERSION should be 1 in a portable application
mysys/my_thr_init.c:
  first, reset THR_KEY_mysys, and then free dbug data,
  because dbug data are automacially created on the next dbug call,
  unless THR_KEY_mysys is null.