Re: meson -Drust=enabled fails on macOS without GNU sed

> On Fri, Dec 12, 2025 at 3:01 PM D. Ben Knoble
> <ben.knoble+github@gmail.com> wrote:
> > I think it's due to e509b5b8be (rust: support for Windows, 2025-10-15)
> > [relevant folks CC'd], where we assume sed can take "-s" (which AFAICT
> > is a GNU extension). But perhaps "-n" was intended with a "p" flag on
> > the substitution?
> >
> > I've been building with Rust enabled on Gentoo now for a minute and
> > haven't hit any issues, but that's perhaps because the command is
> > running with "-s" and not working as intended (yet still producing the
> > expected results).
> >
> > The relevant snippet is this (reformatted slightly by GMail, apologies):
> >
> > case "$(cargo -vV | sed -s 's/^host: \(.*\)$/\1/')" in
> >   *-windows-*) LIBNAME=gitcore.lib;;
> >   *) LIBNAME=libgitcore.a;;
> > esac
> >
> > but "cargo -vV" produces something like
> >
> > cargo 1.89.0 (c24e10642 2025-06-23)
> > [...]
> > host: x86_64-apple-darwin
> >
> > (on my older system, on which I haven't tried the build; the failure
> > is on my newer system with close-enough-to-the-same output). I'm sure
> > you can see why I don't understand why we need GNU's "-s" ("consider
> > files as separate rather than as a single, continuous long stream")
> > here?
> 
> Yup, that's a strange one. Indeed:
> 
>     sed -n 's/^host: \(.*\)$/\1/p'
> 
> would be the correct way to do it, while also being compatible with
> BSD-lineage `sed` (such as `sed` on macOS).