Consolidate non cancellable writev call

This patch consolidates all the non cancellable writev calls to use
the __writev_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.

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

	* gmon/gmon.c (write_hist): Replace writev_not_cancel_no_status with
	__writev_nocancel_nostatus.
	(write_call_graph): Likewise.
	(write_bb_counts): Likewise.
	* resolv/herror.c (herror): Likewise.
	* sysdeps/generic/not-cancel.h (writev_not_cancel_no_status): Remove
	macro.
	(__writev_nocancel_nostatus): New macro.
	* sysdeps/unix/sysv/linux/not-cancel.h (writev_not_cancel_no_status):
	Remove macro.
	(__writev_nocancel_nostatus): New function.