Re: [PATCH 8/8] Makefiles: add and use wildcard "mkdir -p" template

> [...]
> But as it turns out we can use this neat trick of only doing a "mkdir
> -p" if the $(wildcard) macro tells us the path doesn't exist. A re-run
> of a performance test similar to thatnoted downthread of [1] in [2]
> shows that this is faster, in addition to being less verbose and more
> reliable (this uses my "git-hyperfine" thin wrapper for "hyperfine"[3]):

> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> ---
> diff --git a/shared.mak b/shared.mak
> @@ -90,3 +92,18 @@ ifndef V
> +## Is racy, but in a good way; we might redundantly (and safely)
> +## "mkdir -p" when running in parallel, but won't need to exhaustively
> +## individual rules for "a" -> "prefix" -> "dir" -> "file" if given a
> +## "a/prefix/dir/file". This can instead be inserted at the start of
> +## the "a/prefix/dir/file" rule.