Merge remote-tracking branch 'remotes/riku/linux-user-for-upstream' into staging

Merge remote-tracking branch 'remotes/riku/linux-user-for-upstream' into staging

* remotes/riku/linux-user-for-upstream:
  linux-user: fix getrusage and wait4 failures with invalid rusage struct
  linux-user/elfload.c: Support ARM HWCAP2 flags
  linux-user/elfload.c: Fix A64 code which was incorrectly acting like A32
  linux-user/elfload.c: Update ARM HWCAP bits
  linux-user/elfload.c: Fix incorrect ARM HWCAP bits
  linux-user: remove configure option for setting uname release
  linux-user: move uname functions to uname.c
  linux-user: rename cpu-uname -> uname
  linux-user/signal.c: Set fault address in AArch64 signal info
  linux-user: avoid using glibc internals in _syscall5 and in definition of target_sigevent struct
  linux-user: Handle arches with llseek instead of _llseek
  linux-user: Add support for SCM_CREDENTIALS.
  linux-user: Move if-elses to a switch statement.
  linux-user: Assert stack used for auxvec, envp, argv
  linux-user: Add /proc/self/exe open forwarding

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>