Update after gnulib changed.

Update after gnulib changed.

* autogen.sh (GNULIB_MODULES_TOOLS_FOR_SRC_COMMON_DEPENDENCIES): Add
windows-rwlock.
* gettext-runtime/intl/windows-rwlock.h: New file, from gnulib.
* gettext-runtime/intl/windows-rwlock.c: New file, from gnulib.
* gettext-runtime/intl/windows-initguard.h: New file, from gnulib.
* gettext-runtime/intl/windows-spinlock.h: Remove file.
* gettext-runtime/intl/lock.h: Update from gnulib.
* gettext-runtime/intl/lock.c: Likewise.
* gettext-runtime/intl/verify.h: Likewise.
* gettext-runtime/intl/windows-mutex.h: Likewise.
* gettext-runtime/intl/windows-recmutex.h: Likewise.
* gettext-runtime/intl/Makefile.am (EXTRA_DIST): Add windows-rwlock.h,
windows-initguard.h. Remove windows-spinlock.h.
(LIBINTLSOURCES): Conditionally add windows-rwlock.c.
(windows-rwlock.lo): New rule.
(*.lo): Update dependencies.
* Makefile.am (distcheck-hook): Check that gettext-runtime/intl/windows-*.[hc]
are up-to-date.
* gnulib-local/lib/libxml/threads.c: Test HAVE_PTHREAD_H, HAVE_WIN32_THREADS,
HAVE_BEOS_THREADS only if LIBXML_THREAD_ENABLED is defined; otherwise use a
fallback suitable for single-threaded applications.