New program: arch

New program: arch

* NEWS: Mention arch.
* README: Add arch to the list of programs.
* AUTHORS: Add arch.
* src/uname.c: Include "uname.h".
(PROGRAM_NAME): Handle arch, too.
(ARCH_AUTHORS): Define.
(uname_long_options, arch_long_options): Renamed and new globals.
(usage): Handle arch-mode as well as uname-mode.
(decode_switches): New function, extracted from main,
to handle arch-mode as well as uname-mode.
(main): Handle both modes.
* src/uname-arch.c: New program, alias for "uname -m".
* src/uname-uname.c: New file, default uname mode.
* src/uname.h: New file, uname modes.
* src/Makefile.am (EXTRA_PROGRAMS): Add arch.
(uname_SOURCES, arch_SOURCES): Define.
* man/arch.x: New file.
* man/Makefile.am (dist_man_MANS): Add arch.1.
(arch.1): New dependency.
* tests/misc/arch: New test, compare "arch" with "uname -m"
* configure.ac (OPTIONAL_BIN_PROGS): Add arch.
(MAN): Add arch.1.
* .x-sc_require_config_h: Exempt uname-arch.c and uname-uname.c
from the always-include-<config.h> rule.

Signed-off-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Jim Meyering <jim@meyering.net>