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)

Merge from tbemd:

Convert from using MACHINE_ARCH to MACHINE_CPUARCH. Hoist path statement
up into the top Makefile rather than repeating it on every arch Makefile.

Repo copy libpthreads to libkse.
This introduces the WITHOUT_LIBKSE nob,
and changes WITHOUT_LIBPTHREADS to mean with neither threading libs.
Approved by: re(kensmith)

Rethink the MD interfaces for libpthread to account for
archs that can (or are required to) have per-thread registers.

Tested on i386, amd64; marcel is testing on ia64 and will
have some follow-up commits.

Reviewed by: davidxu

Implement _ia64_enter_uts(). The purpose of this function is to switch
the register stack and memory stack and call the function given to it.

While here, provide empty, non-working, stubs for the context functions
(_ia64_save_context() and _ia64_restore_context()) so that anyone can at
least compile libkse from CVS sources. Real implementations will follow
soon.

Untangle the inter-dependency of kse types and ksd types/functions
by moving the definition of struct ksd to pthread_md.h and removing
the inclusion of ksd.h from thr_private.h (which has the definition
of struct kse and kse_critical_t). This allows ksd.h to have inline
functions that use struct kse and kse_critical_t and generally
yields a cleaner implementation at the cost of not having all ksd
related types/definitions in one header.

Implement the ksd functionality on ia64 by using inline functions
and permanently remove ksd.c from the ia64 specific makefile.

This change does not clean up the i386 specific version of ksd.h.

NOTE: The ksd code on ia64 abuses the tp register in the same way
as it is abused in libthr in that it is incompatible with the
runtime specification. This will be address when support for TLS
hits the tree.

Move the machine specific files from sys/Makefile.inc and put them
in a machine specific makefile. While here, sort the sub-directories
in Makefile and remove _atomic_lock.S from all makefiles.