so real syscalls override unix/sysv/*.c on sysv-derived systems
that have them.
* sysdeps/unix/common/syscalls.list: Add settimeofday here, to
override unix/sysv/settimeofday.c since that overrides
unix/syscalls.list.
* Makeconfig (+link): Put $(link-libc) after deps from $^,
regardless of where libc.a appears in the deps.