hurd: Fix link cthread/pthread symbol exposition.
* hurd/Versions (HURD_CTHREADS_0.3): Rename weak refs cthread_fork,
cthread_detach, pthread_getattr_np, pthread_attr_getstack,
cthread_keycreate, cthread_getspecific, cthread_setspecific to
__cthread_fork, __cthread_detach, __pthread_getattr_np,
__pthread_attr_getstack, __cthread_keycreate, __cthread_getspecific,
__cthread_setspecific.
* hurd/hurdsig.c (_hurdsig_init): Use __cthread_fork,
__cthread_detach, __pthread_getattr_np, __pthread_attr_getstack,
__cthread_t instead of cthread_fork, cthread_detach,
pthread_getattr_np, pthread_attr_getstack.
* sysdeps/mach/hurd/cthreads.c (cthread_keycreate): Rename to
__cthread_keycreate.
(cthread_getspecific): Rename to __cthread_getspecific.
(cthread_setspecific): Rename to __cthread_setspecific.
(__libc_getspecific): Use __cthread_getspecific instead of
cthread_getspecific.
* sysdeps/mach/hurd/libc-lock.h (__libc_key_create): Use
__cthread_keycreate instead of cthread_keycreate.
(__libc_setspecific): Use __cthread_setspecific instead of
cthread_setspecific.
* sysdeps/mach/libc-lock.h (__libc_key_create, __libc_setspecific):
Likewise.