Clean pthread functions namespaces for C11 threads

Clean pthread functions namespaces for C11 threads

This patch adds internal definition (through {libc_}hidden_{proto,def}) and
also change some strong to weak alias for symbols that might be used by C11
threads implementations.

The patchset should not change libc/libpthread functional, although object
changes are expected (since now internal symbols are used instead) and final
exported symbols through GLIBC_PRIVATE is also expanded (to cover libpthread
usage of __mmap{64}, __munmap, __mprotect).

Checked with a build for all major ABI (aarch64-linux-gnu, alpha-linux-gnu,
arm-linux-gnueabi, i386-linux-gnu, ia64-linux-gnu, m68k-linux-gnu,
microblaze-linux-gnu [1], mips{64}-linux-gnu, nios2-linux-gnu,
powerpc{64le}-linux-gnu, s390{x}-linux-gnu, sparc{64}-linux-gnu,
tile{pro,gx}-linux-gnu, and x86_64-linux-gnu).

	* include/sched.h (__sched_get_priority_max): Add libc hidden proto.
	(__sched_get_prioriry_min): Likewise.
	* include/sys/mman.h (__mmap): Likewise.
	(__mmap64): Likewise.
	(__munmap): Likewise.
	(__mprotect): Likewise.
	* include/termios.h (__tcsetattr): Likewise.
	* include/time.h (__nanosleep): Use hidden_proto instead of
	libc_hidden_proto.
	* posix/nanosleep.c (__nanosleep): Likewise.
	* misc/Versions (libc): Export __mmap, __munmap, __mprotect,
	__sched_get_priority_min, and __sched_get_priority_max under
	GLIBC_PRIVATE.
	* nptl/allocatestack.c (__free_stacks): Use internal definition for
	libc symbols.
	(change_stack_perm): Likewise.
	(allocate_stack): Likewise.
	* sysdeps/posix/gethostname.c: Likewise.
	* nptl/tpp.c (__init_sched_fifo_prio): Likewise.
	* sysdeps/unix/sysv/linux/i386/smp.h (is_smp_system): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/ioctl.c (__ioctl): Likewise.
	* nptl/pthreadP.h (__pthread_mutex_timedlock): Add definition.
	(__pthread_key_delete): Likewise.
	(__pthread_detach): Likewise.
	(__pthread_cancel): Likewise.
	(__pthread_mutex_trylock): Likewise.
	(__pthread_mutexattr_init): Likewise.
	(__pthread_mutexattr_settype): Likewise.
	* nptl/pthread_cancel.c (pthread_cancel): Change to internal name and
	create alias for exported one.
	* nptl/pthread_join.c (pthread_join): Likewise.
	* nptl/pthread_detach.c (pthread_detach): Likewise.
	* nptl/pthread_key_delete.c (pthread_key_delete): Likewise.
	* nptl/pthread_mutex_timedlock.c (pthread_mutex_timedlock): Likewise.
	* nptl/pthread_create.c: Change static requirements for pthread
	symbols.
	* nptl/pthread_equal.c (__pthread_equal): Change strong alias to weak
	for internal definition.
	* nptl/pthread_exit.c (__pthread_exit): Likewise.
	* nptl/pthread_getspecific.c (__pthread_getspecific): Likewise.
	* nptl/pthread_key_create.c (__pthread_key_create): Likewise.
	* nptl/pthread_mutex_destroy.c (__pthread_mutex_destroy): Likewise.
	* nptl/pthread_mutex_init.c (__pthread_mutex_init): Likewise.
	* nptl/pthread_mutex_lock.c (__pthread_mutex_lock): Likewise.
	* nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock): Likewise.
	* nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock): Likewise.
	* nptl/pthread_mutexattr_init.c (__pthread_mutexattr_init): Likwise.
	* nptl/pthread_mutexattr_settype.c (__pthread_mutexattr_settype):
	Likewise.
	* nptl/pthread_self.c (__pthread_self): Likewise.
	* nptl/pthread_setspecific.c (__pthread_setspecific): Likewise.
	* sysdeps/unix/sysv/linux/tcsetattr.c (tcsetattr): Likewise.
	* misc/mmap.c (__mmap): Add internal symbol definition.
	* misc/mmap.c (__mmap64): Likewise.
	* sysdeps/unix/sysv/linux/mmap.c (__mmap): Likewise.
	* sysdeps/unix/sysv/linux/mmap64.c (__mmap): Likewise.
	(__mmap64): Likewise.
	* sysdeps/unix/sysv/linux/i386/Versions (libc) [GLIBC_PRIVATE):
	Add __uname.