gdb: gdbserver: update ctrl-c handling
A) gdbserver sends SIGINT not to the process, but to the process
group (-signal_pid). But the attached process is not always a
process group leader. If not, "kill (-signal_pid, SIGINT)" returns
error and fails to interrupt the attached process. We cannot interrupt
the process attached with gdbserver who is not a process group leader.
This problem was created by the gdb upstream commit
78708b7c8c
The commit fixed the following case B) bug.
B) We cannot interrupt the process attached with gdbserver whose
main thread exits (pthread_exit()).
Now this patch can solve both A) and B).
Signed-off-by: Zhixiong Chi <zhixiong.chi@windriver.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
