* target.h (target_ops): Change return type of detach to int.
Add join.
(join_inferior): New.
* server.c (main): Don't skip detach support on mingw32.
If the inferior doesn't support detaching return error.
Call join_inferior instead of using waitpid.
* linux-low.c (linux_join): New.
(linux_target_op): Add linux_join.
* spu-low.c (spu_join): New.
(spu_target_ops): Add spu_join.
* win32-low.c (win32_detach): Adapt to new interface.
Reopen current_process_handle before detaching. Issue a child
resume before detaching.
(win32_join): New.
(win32_target_op): Add win32_join.