Debug build on Windows is broken: error LNK2019: unresolved external symbol pthread_detach referenced in function ma_checkpoint_init

aria.lib(ma_checkpoint.obj) : error LNK2019: unresolved external symbol _pthread_detach referenced in function _ma_checkpoint_init [C:\bzr\bb-win32\win32-debug2\build\sql\mysqld.vcxproj]

C:\bzr\bb-win32\win32-debug2\build\sql\Debug\mysqld.exe : fatal error LNK1120: 1 unresolved externals [C:\bzr\bb-win32\win32-debug2\build\sql\mysqld.vcxproj]

Done Building Project "C:\bzr\bb-win32\win32-debug2\build\sql\mysqld.vcxproj" (default targets) -- FAILED.

     {

       /* thread lives, will have to be killed */

       checkpoint_control.status= THREAD_RUNNING;

+      pthread_detach(th);

     }

   }

   DBUG_RETURN(res);