acpi,pc,build bug fixes

Here are some bugfixes for 2.0.

A bugfix for acpi for pci bridges, and a build fix for
old systems without pthread_setname_np: both fix regressions
so we definitely want to include them.
HPET fix is not for a regression but looks very safe,
fixes a nasty bug and has been on list for a while.
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

# gpg: Signature made Fri 28 Mar 2014 12:00:12 GMT using RSA key ID D28D5469
# gpg: Good signature from "Michael S. Tsirkin <mst@kernel.org>"
# gpg:                 aka "Michael S. Tsirkin <mst@redhat.com>"

* remotes/mst/tags/for_upstream:
  acpi: fix ACPI generation for pci bridges
  Don't enable a HPET timer if HPET is disabled
  Detect pthread_setname_np at configure time
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>