Use __pthread_setcancelstate in libc.a

Use __pthread_setcancelstate in libc.a

This patch references __pthread_setcancelstate instead of
pthread_setcancelstate in libc.a.

	[BZ #18970]
	* misc/error.c (error): Replace pthread_setcancelstate with
	__pthread_setcancelstate.
	(error_at_line): Likewise.
	* posix/wordexp.c (parse_comm): Likewise.
	* stdlib/fmtmsg.c (fmtmsg): Likewise.
	* nptl/forward.c (pthread_setcancelstate): Renamed to ...
	(__pthread_setcancelstate): This.
	(pthread_setcancelstate): Add an alias.
	* nptl/nptl-init.c (pthread_functions): Replace
	ptr_pthread_setcancelstate with ptr___pthread_setcancelstate.
	* sysdeps/nptl/pthread-functions.h (pthread_functions): Likewise.
	* nptl/pthreadP.h (__pthread_setcancelstate): Mark it with
	hidden_proto.
	* nptl/pthread_setcancelstate.c (__pthread_setcancelstate): Mark
	it with hidden_def.
	* sysdeps/nptl/libc-lockP.h (__pthread_setcancelstate): New.
	(pthread_setcancelstate): Renamed to ...
	(__pthread_setcancelstate): This.
	* sysdeps/unix/sysv/linux/fatal-prepare.h (FATAL_PREPARE): Use
	__libc_ptf_call with __pthread_setcancelstate.