maint: update copyright notices to include 2013.

maint: update copyright notices to include 2013.

* gnulib/: Update to latest upstream.
* AUTHORS, ChangeLog.old, HACKING, Makefile.am, NEWS, README,
THANKS, TODO, bootstrap, bootstrap.conf,
build-aux/edit-readme-alpha, build-aux/ltmain.in, cfg.mk,
configure.ac, doc/libtool.texi, gl/build-aux/bootstrap.in,
gl/build-aux/extract-trace, gl/build-aux/funclib.sh,
gl/build-aux/inline-source, gl/build-aux/options-parser,
libltdl/README, libltdl/argz.c, libltdl/argz_.h,
libltdl/configure.ac, libltdl/libltdl/lt__alloc.h,
libltdl/libltdl/lt__dirent.h, libltdl/libltdl/lt__glibc.h,
libltdl/libltdl/lt__private.h, libltdl/libltdl/lt__strl.h,
libltdl/libltdl/lt_dlloader.h, libltdl/libltdl/lt_error.h,
libltdl/libltdl/lt_system.h, libltdl/libltdl/slist.h,
libltdl/loaders/dld_link.c, libltdl/loaders/dlopen.c,
libltdl/loaders/dyld.c, libltdl/loaders/load_add_on.c,
libltdl/loaders/loadlibrary.c, libltdl/loaders/preopen.c,
libltdl/loaders/shl_load.c, libltdl/lt__alloc.c,
libltdl/lt__dirent.c, libltdl/lt__strl.c, libltdl/lt_dlloader.c,
libltdl/lt_error.c, libltdl/ltdl.c, libltdl/ltdl.h,
libltdl/ltdl.mk, libltdl/slist.c, libtoolize.in, m4/argz.m4,
m4/autobuild.m4, m4/libtool.m4, m4/ltdl.m4, m4/ltoptions.m4,
m4/ltsugar.m4, m4/ltversion.in, m4/lt~obsolete.m4,
tests/am-subdir.at, tests/archive-in-archive.at,
tests/bindir.at, tests/cdemo.at, tests/cmdline_wrap.at,
tests/configure-iface.at, tests/convenience.at, tests/ctor.at,
tests/cwrapper.at, tests/darwin.at, tests/demo.at,
tests/depdemo.at, tests/deplib-in-subdir.at,
tests/deplibs-ident.at, tests/deplibs-mingw.at,
tests/destdir.at, tests/dlloader-api.at,
tests/dumpbin-symbols.at, tests/duplicate_conv.at,
tests/duplicate_deps.at, tests/duplicate_members.at,
tests/early-libtool.at, tests/exceptions.at,
tests/execute-mode.at, tests/exeext.at, tests/export.at,
tests/f77demo.at, tests/fail.at, tests/fcdemo.at,
tests/flags.at, tests/help.at, tests/indirect_deps.at,
tests/infer-tag.at, tests/inherited_flags.at, tests/install.at,
tests/lalib-syntax.at, tests/libtool.at, tests/libtoolize.at,
tests/link-order.at, tests/link-order2.at, tests/loadlibrary.at,
tests/localization.at, tests/lt_dladvise.at, tests/lt_dlexit.at,
tests/lt_dlopen.at, tests/lt_dlopen_a.at, tests/lt_dlopenext.at,
tests/ltdl-api.at, tests/ltdl-libdir.at, tests/mdemo.at,
tests/need_lib_prefix.at, tests/no-executables.at,
tests/nocase.at, tests/nonrecursive.at, tests/old-ltdl-iface.at,
tests/old-m4-iface.at, tests/pic_flag.at, tests/recursive.at,
tests/resident.at, tests/runpath-in-lalib.at,
tests/search-path.at, tests/shlibpath.at, tests/slist.at,
tests/standalone.at, tests/static.at, tests/stresstest.at,
tests/subproject.at, tests/sysroot.at, tests/tagdemo.at,
tests/template.at, tests/testsuite.at, tests/versioning.at,
tests/with-pic.at: Bump copyright year.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>