Remove false support for power and mips.
Fix aarch64 definitions of nlink_t and blksize_t.

Signed-off-by: Ian Henry <ihenry@chef.io>

The futimes(), lutimes(), mq_timedreceive(), and mq_timedsend()
functions were linking against legacy library symbols that need 32-bit
time_t in structures, resulting in an ABI mismatch with 64-bit time_t.

Looks like Travis has moved on from our old images, so we're forced to
update.

HermitCore is based on lwIP, newlib, and pthread-embedded.

This reverts commit 920cfeac.

These are flags required to implement the linux kernel loading mechanism.
Specifically finit_module.

they doesn't exists on OpenBSD. put them under NetBSD specific tree.

It looks like this was a mistake of #930 but should be easy to fix!