Adjust to Autoconf 2.60 and today's gnulib.

Adjust to Autoconf 2.60 and today's gnulib.
* bootstrap (gnulib_modules): Add stdint.
Remove special case for m4/onceonly_2_57.m4, since gnulib-tool
no longer copies it.
(intl_files_to_remove): Remove m4/longlong.m4 and m4/wchar_t.m4,
since stdint needs the former and wcwidth (which is now required
by mbswidth) needs the latter.
Append 'datarootdir = @datarootdir@' to po/Makefile.in.in, to
work around a compatibility glitch between gettext 0.14.6 and
Autoconf 2.60.
* configure.ac (AC_PREREQ): Require Autoconf 2.60.
Do not check for uintptr_t, since new stdint module does the right
thing.
* lib/.cvsignore: Remove alloca.c, alloca.h, alloca_.h.
Add stdint.h, stdint_.h, wcwidth.h.
* m4/.cvsignore: Remove alloca.m4, onceonly.m4.
Add absolute-header.m4, double-slash-root.m4, longlong.m4,
stdint.m4, wchar_t.m4, wcwidth.m4.
* src/files.c: Include <dirname.h> and <stdio-safer.h> in the
usual order for ../lib/*.h files.
(file_name_split): Use last_component, not base_name, to adjust
to gnulib changes.
* src/parse-gram.h: Include <strverscmp.h> in the usual order
for ../lib/*.h files.
(YYTYPE_INT16, YYTYPE_INT8, YYTYPE_UINT16, YYTYPE_UINT8):
Define unconditionally, since we now assume the stdint module.
* src/scan-skel.l: Include <dirname.h>.
(BASE_QPUTS): Use last_component, not base_name.
* src/system.h: Include <unlocked-io.h> in the usual order
for ../lib/*.h files.  Include <stdint.h> unconditionally,
since we now use the stdint module.
(uintptr_t): Declare if UINTPTR_MAX is not defined, not
HAVE_UINTPTR_T, since we now use the stdint module.
(base_name): Remove decl, since files now include <dirname.h>
to get the decl.