Make cpu_single_env thread-local Make cpu_single_env thread-local. This fixes a regression in handling of multi-threaded programs in linux-user mode (bug 823902). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [Peter Maydell: rename tls_cpu_single_env to cpu_single_env] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Andreas Färber <afaerber@suse.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>