Fix syscall names for aarch64
Fix portability issues when using Valgrind (make -C tests/ memcheck).
Merge remote-tracking branch 'ivoire/master' into next
Fix build for ARM64 (a.k.a. AArch64).

Note that execution on ARM64 is not officially supported yet, there are
known issues:

  CHECK test-071599da FAILED
  CHECK test-092c5e26 FAILED
  CHECK test-1ffc8309 FAILED
  CHECK test-1ffc8309 FAILED
  CHECK test-5bed7143 FAILED
  CHECK test-5bed7143 FAILED
  CHECK test-kkkkkkkk FAILED

Reported-by: Rémi Duraffort <remi.duraffort@st.com>
Thanks-to: Rémi Duraffort <remi.duraffort@st.com> for the Debian/ARM64 system.
Fix renameat sysexit support.

This bug was exposed by test 5bed7143 on Arm64 only because on this
architecture rename(2) is implemented with the renameat syscall.