Instead of having a generic "virt_qemu" board use "virt_qemu_<arch>" in
order to have a clean distinction between boards. Current supported
boards are "virt_qemu_arm_v7a", "virt_qemu_arm_v8a", and
"virt_qemu_riscv".
issue #4034
This patch removes the reliance of the extract tool from the libc's
behavior regarding the access of time and timing.
The extract tool is not expected to need time. However, unfortunately,
libarchive calls the 'time' function unconditionally. By adding a
dummy for 'time', we avoid bothering the libc, which would otherwise
need to obtain a time source.
Issue #3204
