Merge from gnulib, using build-aux to remove clutter (Bug#9169).

Merge from gnulib, using build-aux to remove clutter (Bug#9169).

This is to fix the following problems:
 . On FreeBSD 6.4, HP-UX 11.31, and Solaris 9, and when Emacs is
   configured not to use gtk or any other thread-using library,
   signals aren't blocked correctly.
 . On IRIX 6.5 it fixes an unwanted clash between Emacs's
   and IRIX's signal handling.
 . On Cygwin 1.7.5 it works around an incompatibility with
   the system pthread_sigmask.
 . On MacOS X 10.5 (32-bit), files whose inode numbers
   exceed 2**31 cannot be read or manipulated.
 . pthread_sigmask: Actually use results of gl_THREADLIB.
 . strtoimax, strtoumax: Avoid link error on OSF/1 with DTK cc.
 . find 'ar' program that fits with --host argument.
 . Allow the user to override the choice of AR, ARFLAGS, RANLIB.

* autogen/README: Update destination list.
* autogen/copy_autogen, autogen/update_autogen, .bzrignore:
The autogenerated files compile, config.guess,
config.sub, depcomp, install-sh, and missing are now in build-aux.
* m4/largefile.m4: New file, so that Emacs does not mess up when
accessing files with large inode numbers in MacOS X 10.5 and later.
* m4/nocrash.m4: New file, to avoid triggering background debugger
and/or create core dumps during 'configure'.
* build-aux/move-if-change: Renamed from move-if-change.
* build-aux/snippet/arg-nonnull.h: Renamed from arg-nonnull.h.
* build-aux/snippet/c++defs.h: Renamed from c++defs.h.
* build-aux/snippet/warn-on-use.h: Renamed from warn-on-use.h.
* build-aux/snippet/_Noreturn.h: New file, for draft C1X _Noreturn.
* Makefile.in (epaths-force, sync-from-gnulib):
move-if-change is now in build-aux.
(GNULIB_TOOL_FLAGS): Avoid threadlib; this is now a prerequisite
of gnulib's pthread_sigmask module, but Emacs doesn't need it.
(mkdir): install-sh is now in build-aux.
* config.bat: c++defs.h is now in build-aux/snippets.
* configure.in: Specify AC_CONFIG_AUX_DIR with build-aux (the
usual parameter).
* lib/gnulib.mk, m4/gl-comp.m4: Regenerate.
* lib/makefile.w32-in (ARG_NONNULL_H): arg-nonnull.h moved
to build-aux/snippet.
* lib/pthread_sigmask.c, lib/stdlib.in.h, m4/extensions.m4:
* m4/getopt.m4, m4/gnulib-common.m4, m4/pthread_sigmask.m4:
Merge from gnuilib.  This fixes porting bugs on Cygwin, Irix, and
Solaris, enables MacOS extensions, and enables nocrash during
'configure'.
* make-dist: Adjust to new build-aux and build-aux/snippit dirs.
* admin/notes/copyright: The files compile, config.guess, config.sub,
depcomp, install-sh, missing, and move-if-change are now in the
new build-aux subdirectory.  The files arg-nonnull.h, c++defs.h,
and warn-on-use.h are now in build-aux/snippets.  New file
build-aux/snippets/_Noreturn.h.
* leim/Makefile.in (install): install-sh is now in build-aux (Bug#9169).
* lib-src/Makefile.in ($(DESTDIR)${archlibdir}): install-sh moved
to build-aux (Bug#9169).
* msdos/sedlibmk.inp (CONFIG_CLEAN_VPATH_FILES): Adjust to snippet moves
from top level to build-aux/snippet (Bug#9169).
* src/Makefile.in (gl-stamp): move-if-change now in build-aux (Bug#9169).