9f52f2295e
let these use the same setting as the rest of the tree. the performance difference is marginal and this allows dtrace ustack() to work better.
$NetBSD: README,v 1.7 2017/02/08 03:44:41 kamil Exp $ Due to limitations in the current pthread implementation, makecontext(3) and sigaltstack(2) should not be used in programs which link against libpthread (whether threads are used or not). This has been noted in the makecontext(3), sigaltstack(2), and pthread(3) man pages.