Log Message:
various fixes for arm64 big endian support.

most of these simply extend matching from "aarch64" to \ 
"aarch64eb"
in various forms of code.  most remaining uses in pkgsrc of
"MACHINE_ARCH == aarch64" are because of missing aarch64eb support,
such as most of the binary-bootstrap requiring languages like rust,
go, and java.

no pkg-bump because this shouldn't change packages on systems that
could already build all of these.