Consolidate non cancellable read call

This patch consolidates all the non cancellable read calls to use
the __read_nocancel identifier.  For non cancellable targets it will
be just a macro to call the default respective symbol while on Linux
will be a internal one.

Also, since it is used on libcrypto it is also exported in GLIBC_PRIVATE
namespace.

Checked on x86_64-linux-gnu, x86_64-linux-gnu-x32, and i686-linux-gnu.

	* sysdeps/generic/not-cancel.h (read_not_cancel): Remove macro.
	(__read_nocancel): New macro.
	* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
	__read_nocancel.
	* sysdeps/unix/sysv/linux/not-cancel.h (__read_nocancel): Remove
	macro.
	(__read_nocancel): New prototype.
	* sysdeps/unix/sysv/linux/read.c (__read_nocancel): New function.
	* catgets/open_catalog.c (__open_catalog): Replace read_not_cancel
	with __read_nocancel.
	* intl/loadmsgcat.c (read): Likewise.
	* libio/fileops.c (_IO_file_read): Likewise.
	* locale/loadlocale.c (_nl_load_locale): Likewise.
	* login/utmp_file.c (getutent_r_file): Likewise.
	(internal_getut_r): Likewise.
	(getutline_r_file): Likewise.
	* sysdeps/unix/sysv/linux/fips-private.h (fips_enable_p): Likewise.
	* sysdeps/unix/sysv/linux/gethostid.c (gethostid): Likewise.
	* sysdeps/unix/sysv/linux/getloadavg.c (getloadavg): Likewise.
	* sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid):
	Likewise.
	* sysdeps/unix/sysv/linux/getsysstats.c (next_line): Likewise.
	* sysdeps/unix/sysv/linux/i386/smp.h (is_smp_system): Likewise.
	* sysdeps/unix/sysv/linux/ia64/has_cpuclock.c (has_cpuclock):
	Likewise.
	* sysdeps/unix/sysv/linux/libc_fatal.c (backtrace_and_maps):
	Likewise.
	* sysdeps/unix/sysv/linux/malloc-sysdep.h (check_may_shrink_heap):
	Likewise.
	* sysdeps/unix/sysv/linux/pthread_getname.c (pthread_getname_np):
	Likewise.
	* sysdeps/unix/sysv/linux/sysconf.c (__sysconf): Likewise.

sysdeps/unix/sysv/linux/malloc-sysdep.h

@@ -47,7 +47,7 @@ check_may_shrink_heap (void)
       if (fd >= 0)
 	{
 	  char val;
-	  ssize_t n = read_not_cancel (fd, &val, 1);
+	  ssize_t n = __read_nocancel (fd, &val, 1);
 	  may_shrink_heap = n > 0 && val == '2';
 	  close_not_cancel_no_status (fd);
 	}