don't fail with EINTR in sigtimedwait
don't fail with EINTR in sigtimedwait

POSIX allows either behavior, but sigwait is not allowed to fail with
EINTR, so the retry loop would have to be in one or the other anyway.

chardi/musl,rofl0r/musl-old,chardi/musl,chneukirchen/musl-chris2,davidlazar/musl,davidlazar/musl,chardi/musl,chneukirchen/musl-chris2,rofl0r/musl-old