Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix n32 compile.

These changes are needed to fix n32 compile after the recent change of
mips n32 MACHINE_ARCH to mipsn32eb/mipsn32el.

Reviewed by: imp, bz (earlier version)

Retire TARGET_ABI.

Implement MACHINE_ARCH=mips64e[lb] to build N64 images. This replaces
MACHINE_ARCH=mipse[lb] TARGET_ABI=n64.

MACHINE_ARCH=mipsn32e[lb] has been added, but currently requires
WITHOUT_CDDL due to atomic issues in libzfs. I've not investigated
this much, but implemented this to preserve as much of the TARGET_ABI
functionality that I could. Since its presence doesn't affect the
working cases, I've kept it in for now.

Added mips64e[lb] to make universe, so more kernels build.

And I think this (finally) closes the curtain on the tbemd tree.

Merge from tbemd: use Makefile.arch to control building.

Reviewed by: arch@ (many times, no objection)