Prevent exit status from being clobbered on thread exit.

Ensure that EXIT_NORMAL only runs once by guarding it with PS_EXITING.

It was previously possible for EXIT_NORMAL to be run twice, depending on
which thread called exit() and the order in which the threads were torn
down. This is due to the P_HASSIBLING() check triggering the last thread
to run EXIT_NORMAL, even though it may have already been run via an exit()
call.

ok kettenis@ visa@

0 files changed, 0 insertions, 0 deletions