The _exit syscall is used for both thread termination in NPTL applications, and process termination in legacy applications. Try to guess which we want based on the presence of multiple threads. Also implement locking when modifying the CPU list. Signed-off-by: Paul Brook <paul@codesourcery.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6735 c046a42c-6fe2-441c-8c8c-71466251a162