hppa-linux target support

# gpg: Signature made Mon 23 Jan 2017 17:54:09 GMT
# gpg:                using RSA key 0xAD1270CC4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"
# Primary key fingerprint: 9CB1 8DDA F8E8 49AD 2AFC  16A4 AD12 70CC 4DD0 279B

* remotes/rth/tags/pull-hppa-20170123: (25 commits)
  target-hppa: Implement floating-point insns
  target-hppa: Implement system and memory-management insns
  target-hppa: Implement loads and stores
  target-hppa: Implement shifts and deposits
  target-hppa: Implement linux-user gateway page
  target-hppa: Implement branches
  target-hppa: Implement basic arithmetic
  target-hppa: Add nullification framework
  target-hppa: Add framework and enable compilation
  target-hppa: Add softfloat specializations
  linux-user: Add HPPA startup and main loop
  linux-user: Add HPPA signal handling
  linux-user: Add HPPA target_signal.h and target_cpu.h
  linux-user: Add HPPA target_structs.h
  linux-user: Add HPPA definitions to syscall_defs.h
  linux-user: Add HPPA target_syscall.h
  linux-user: Add HPPA termbits.h
  linux-user: Add HPPA syscall numbers
  linux-user: Add HPPA socket.h definitions
  linux-user: Add some hppa ioctls
  ...
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>