hppa build broken

[Florian Weimer]

In file included from tst-mutex5.c:27:
tst-mutex5.c: In function ‘do_test_clock’:
tst-mutex5.c:76:19: error: implicit declaration of function ‘pthread_mutex_clocklock’; did you mean ‘pthread_mutex_unlock’? [-Werror=implicit-function-declaration]
   76 |     TEST_COMPARE (pthread_mutex_clocklock (&m, clockid, &ts_timeout),
      |                   ^~~~~~~~~~~~~~~~~~~~~~~
../support/check.h:103:28: note: in definition of macro ‘TEST_COMPARE’
  103 |     typedef __typeof__ (+ (left)) __left_type;                          \
      |                            ^~~~

I think this is because the hppa copy of pthread.h wasn't updated for
the recent nptl changes.

I will fix this tomorrow if no one else steps in before that.

Thanks,
Florian