* bootstrap: Update from gnulib.
* bootstrap.conf (gnulib_tool_option_extras): Define.
* lib/Makefile.am: Initialize numerous automake variables so that
generated code in gnulib.mk may use += to append to them.
* configure.ac: Add AM_PROG_AR, to placate newer automake.
* bootstrap: Update from gnulib.
* cfg.mk (local-checks-to-skip): Remove (thus, enable)
sc_copyright_check, now that the gnulib submodule is up to date.
* configure.ac: Add automake and gnulib macros, replace several
obsolete macros.
* Makefile.am, lib/Makefile.am, src/Makefile.am, tests/Makefile.am:
Add for automake.
* autogen.sh, INSTALL, Makefile.in, mkinstalldirs, update-version.sh:
Obsolete; remove.
* README-hacking: Import from diffutils, replace cvs with git.
* build-aux: Move gnulib auxiliary files here from the top-level
directory.
* gnulib: Add gnulib git submodule.
* bootstrap, bootstrap.conf: Import from gnulib and adjust.
* gl/lib: Remove gnulib files from the repository; they are now
imported into lib/ from gnulib as needed.
* tests/test-lib.sh: Use $abs_top_builddir exported from
tests/Makefile.am here instead of $PWD.
* m4/utimbuf.m4: This macro has been removed from gnulib. Add it here
for now; this will be replaced by gnulib's utimens module soon.
