y2038: nptl: Convert pthread_mutex_{clock|timed}lock to support 64 bit

The pthread_mutex_clocklock and pthread_mutex_timedlock have been converted
to support 64 bit time.

This change uses:
- New __futex_clocklock_wait64 (instead of lll_timedwait)

from ./sysdeps/nptl/futex-helpers.c and

- New __futex_clocklock64 function (instead of lll_clocklock)
- New futex_lock_pi64

defined in sysdeps/nptl/futex-internal.h

The pthread_mutex_{clock|timed}lock only accepts absolute time.
Moreover, there is no need to check for NULL passed as *abstime pointer to the
syscalls as those calls have exported symbols marked with __nonull attribute
for abstime.

Some architectures - namely x86, powerpc and s390 - do support lock elision.
For those - adjustments have been made in arch specific elision-*.c files
to use __futex_clocklock64 instead of lll_clocklock.
The __lll_lock_elision (aliased to __lll_clocklock_elision in e.g.
sysdeps/unix/sysv/linux/s390/elision-timed.c) just uses, in this patch
provided, __futex_clocklock64.

For systems with __TIMESIZE != 64 && __WORDSIZE == 32:
- Conversions between 64 bit time to 32 bit are necessary
- Redirection to pthread_mutex_{clock|timed}lock will provide support for 64
bit time

Build tests:
./src/scripts/build-many-glibcs.py glibcs

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

nptl/pthreadP.h

@@ -468,6 +468,8 @@ extern int __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex);
 # define __pthread_rwlock_clockwrlock64 __pthread_rwlock_clockwrlock
 # define __pthread_rwlock_timedrdlock64 __pthread_rwlock_timedrdlock
 # define __pthread_rwlock_timedwrlock64 __pthread_rwlock_timedwrlock
+# define __pthread_mutex_clocklock64 __pthread_mutex_clocklock
+# define __pthread_mutex_timedlock64 __pthread_mutex_timedlock
 #else
 extern int __pthread_clockjoin_np64 (pthread_t threadid, void **thread_return,
                                      clockid_t clockid,
@@ -499,6 +501,13 @@ libpthread_hidden_proto (__pthread_rwlock_timedrdlock64)
 extern int __pthread_rwlock_timedwrlock64 (pthread_rwlock_t *rwlock,
                                            const struct __timespec64 *abstime);
 libpthread_hidden_proto (__pthread_rwlock_timedwrlock64)
+extern int __pthread_mutex_clocklock64 (pthread_mutex_t *mutex,
+                                        clockid_t clockid,
+                                        const struct __timespec64 *abstime);
+libpthread_hidden_proto (__pthread_mutex_clocklock64)
+extern int __pthread_mutex_timedlock64 (pthread_mutex_t *mutex,
+                                        const struct __timespec64 *abstime);
+libpthread_hidden_proto (__pthread_mutex_timedlock64)
 #endif
 
 extern int __pthread_cond_timedwait (pthread_cond_t *cond,